Advice
September 10, 2025

How to Create a Thunderbird Email Signature?

By
Letsignit

With its high level of security, open source code, and multiple features, it's no wonder that Thunderbird is so popular!

And like any email client worth its salt, the platform also offers the option of adding an email signature, a valuable marketing tool and interface between you and your audience.

Today, we'll explain how to create, add, and edit an email signature in Thunderbird for effective communication!

How to Add an Automatic Signature in Thunderbird Email?

Thunderbird automatic signature

Thunderbird allows you to set up an automatic email signature in a few simple steps.

You can choose between three options: enter your text signature directly, enter an HTML signature, or use an external file in text or HTML format.

Please note: command names may vary from one version of Thunderbird to another, for example due to updates. If you cannot find the exact commands mentioned in this guide, look for similar commands.

And to find out which signature format to choose depending on your use, don't miss our guide to the different email signature formats!

Mozilla Thunderbird Email Signature Settings

Thunderbird email signature settings

The Thunderbird signature settings allow you to configure how your signature appears in new messages and replies. This email client provides flexible options for managing your signature across different accounts.

01Text Format

Choose this option for a quick and minimalist email signature that includes your main information.

  1. In Thunderbird, go to Menu (or the ☰ symbol) > Settings > Account Settings.
  2. Select your email account from the left panel.
  3. In the signature section, enter your signature directly (for example: your name, job title, phone numbers, etc.).
  4. To keep it in plain text mode, make sure the "Use HTML" box is unchecked.
  5. Save your signature by clicking OK.

02With HTML Code

If you want to customize your email signature by adding images, your company logo, an email banner, or dynamic links, opt for an HTML format signature.

First option: manually configure the formatting of your signature by typing your HTML code yourself, especially for simple settings such as bolding (tag: <b> and </b>) or inserting a link (tag: <a href="https://www.yoursite.com/"> and </a>).

Here is a guide to the main tags if you're feeling tech-savvy!

Here's how to create your Thunderbird email signature in HTML format:

  1. Go to Account Settings as described above.
  2. Select your email account.
  3. Check the box "Use HTML" in the signature section.
  4. Manually enter or copy and paste your HTML code into the text field. You can take this opportunity to add the URLs of your links, logos, banners, and images hosted on online software.
  5. Save by clicking OK.

Want all the keys to a super professional email signature? Find out in detail how to create an email signature, with examples of signatures that hit the mark.

03From an External File

Have you created and downloaded your signature from email signature generators such as Canva? You can use it by selecting the HTML or text file saved on your computer.

  1. Go to Account Settings as described above.
  2. Select your email account.
  3. Check the box "Attach signature from file".
  4. Click "Choose" to browse for your file.
  5. Select your file in .txt or .html format.

How Do I Add an Image to My Thunderbird Email Signature?

Image thunderbird email

Do you already have an email signature in image format and want to integrate it into your Thunderbird emails? This is entirely possible, but with a few limitations.

First, it is not possible to integrate image files hosted locally (i.e., on your computer) directly from the settings. The only way to use a local image file is to insert it directly into each email, but then the signature will not be automatically integrated... Not the most efficient solution!

To use an image file as a signature, it's best to use an external editor (Letsignit, Canva, MySignature, etc.). You can then either copy and paste the signature URL into the HTML field or use the .html or .txt file stored on your computer. Both methods are described above!

By the way: your recipients can also enjoy your beautiful email signature on their smartphones! Here's how to add an email signature on mobile.

How Do I Add a Signature in Thunderbird With Both Image/Logo and Text?

To create a signature combining both image and text elements:

  1. Use the HTML code method in your Thunderbird signature settings
  2. Include your text content with appropriate HTML formatting
  3. Add image tags (<img src="your-image-url">) for logos or photos
  4. Include social media icons using hosted image URLs
  5. Ensure proper formatting for both text and visual elements

If you're not sure how to create the HTML code, you can use a free solution like Word to HTML to help you.

How Do I Add a Hyperlink in a Thunderbird Email Signature?

Link thunderbird email signature

Adding hyperlinks to your Thunderbird signature enhances its functionality:

  1. Use the HTML code method in your signature settings
  2. Create links using the anchor tag: <a href="https://yourwebsite.com">Link Text</a>
  3. Add links to phone numbers: <a href="tel:+1234567890">Call Us</a>
  4. Include email links: <a href="mailto:contact@company.com">Email Us</a>
  5. Link social media icons to your profiles using the <img src="your-image-url"> code snippet.

How Do I Add a Thunderbird Signature to My Reply or Forward Emails?

Once you have configured your email signature, it should normally appear automatically in all your messages, including reply and forward emails.

However, if your signature does not appear, or if you want to customize this feature, you can follow these steps:

  1. Go to Account Settings (as described above).
  2. Select your email account.
  3. Look for "Composing & Addressing" in the account settings.
  4. You can then check or uncheck the options "Include signature when replying" and/or "Include signature when forwarding".

Where Does Thunderbird Store Signatures?

Want quick access to your different email signatures in Thunderbird? Go to Account Settings, select your email account, then look for the signature section (usually found directly in the account settings or under an "Identity" section). There, you can edit your signature in text or HTML as described above.

How Do I Change the Position of the Thunderbird Signature?

Thunderbird also gives you the option to change the position of your email signature. You can place your signature at the very bottom of the email, or just after your message.

To do this:

  1. Go to Account Settings.
  2. Select your account in the left panel.
  3. Look for signature placement options.
  4. Choose one of the following options: "Below my reply (above the quoted message)" or "At the end of the message (after the quoted text)".

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We hope this guide to Thunderbird email signatures has enlightened you, like a bolt of lightning streaking across the night sky...

What's that? You're more of a Microsoft fan? Don't worry: you too can set up a beautiful electronic business card. Here's how to create an impressive Outlook email signature!

About the author
About Letsignit
Letsignit is an email signature management solution that empowers organizations to turn employee email signatures into a dynamic and personalized engagement channel for their brands and campaigns.

Questions
Fréquentes

1

Is it possible to track the number of clicks on email signatures?

Yes, with the 'Campaigns' offer, it is possible to track the number of clicks on the email signatures of all your employees in the 'Statistics' area of the platform.

You can then access a detailed or global view of the number of clicks on the email signatures of each employee. You can use the search option to target a specific signature or a given period. Finally, you have the possibility to export all statistics to an Excel document.

If you launch campaigns with banners inserted in your email signatures, you can also access their performance via this same space.

2

Can we add links to social networks, our website, and appointment-setting applications such as Calendly?

With Letsignit, you can easily add social network icons in your collaborators' email signatures and link to your company pages. Also, our "attributes" feature allows you to manage personalized URLs for each of your collaborators such as their individual LinkedIn profile.

And that's not all: you can add links to an appointment-setting application, allow your customers to leave reviews easily, and integrate our 'Chat on Teams' widget to let anyone start a discussion via Microsoft Teams chat.

3

Can employees update their signature information themselves (number, function, etc.)?

It’s up to you! As an administrator of the Letsignit platform, you choose whether or not to grant modification rights to your employees. These permissions are managed on an attribute-by-attribute basis, which means that you can decide to allow the employee to change their phone number, but not the address of your premises, for example.

This feature applies to all attributes in your directory, including custom attributes created on Letsignit. When your employees change one or more attributes, your directory is obviously not affected.

4

Why it is important to standardize our email signatures on a large scale to ensure our identity and brand image?

It often happens that employees make their email signature their own: custom format, bad fonts, colors inconsistent with the brand standards... all of this has an impact on your brand!

A consistent visual identity is considered authentic and outperforms a perceived weak one by 20%. And, your customers are 2.4 times more likely to buy your products.

With Letsignit, take back control over your brand identity by standardizing all your email signatures. Our tool has many features that allow you to customize your signatures by department, by audience or by subsidiary. Not to mention the possibility of carrying out campaigns within your email signatures thanks to our Campaign offer.

5

What is the user experience like for our employees?

What is the user experience like for our employees?

  • If you opt for the Letsignit Add-in for Outlook, they will have a dedicated space in their Outlook account where they will be able to view the signatures and campaigns assigned to them.
  • If you opt for the Letsignit Desktop APP, they will be able to preview all their signatures and campaigns in this space. If they want to change their default signature to another one when sending an email, this will be done in their signature library in Outlook.

In both cases:

  • They preview their signature before sending an email and choose from signatures assigned to them.
  • Based on the permissions granted, they will also be able to modify their personal information such as their name, position, or address in these spaces.

In short, they have autonomy in their email signature, but you keep control on the field, signatures, and banners they can edit or use.

6

Can my employees have multiple signatures available to them?

With our "multi-signature" feature, your employees can benefit from multiple email signatures. No technical manipulation is required. Thanks to our Add-in for Outlook or the desktop app, they can change their email signatures as they wish with just a few clicks.

Regarding the creation of email signatures, you can make several variations such as:

Everything has been thought of to go further in the personalization process based on the recipient of your emails.

7

Regarding “Green IT,” have you implemented measures to limit the digital footprint of email signatures?

If sending emails has an impact, non-optimized email signatures also have an impact. An unsuitable format or an image that is too heavy considerably increases the size of your signatures... and therefore, your emails.

As a responsible economic actor, we contribute to reducing our CO2 emissions and those of our customers in several ways:

  • Optimization of the weight of signatures and campaigns in emails.
  • Green features: lightening of signatures during response/transfer emails, possibility of not embedding images, implementation of lighter signatures for internal exchanges.
  • Integration of a 'Switch to Teams' widget to encourage your employees to continue their exchanges via chat, rather than email.

As we are increasingly involved in sustainability initiatives, our priority in 2023 is to develop even more green IT functionality.

8

Regarding “Green IT,” have you implemented measures to limit the digital footprint of email signatures?

If sending emails has an impact, non-optimized email signatures also have an impact. An unsuitable format or an image that is too heavy considerably increases the size of your signatures... and therefore, your emails.

As a responsible economic actor, we contribute to reducing our CO2 emissions and those of our customers in several ways:

  • Optimization of the weight of signatures and campaigns in emails.
  • Green features: lightening of signatures during response/transfer emails, possibility of not embedding images, implementation of lighter signatures for internal exchanges.
  • Integration of a 'Switch to Teams' widget to encourage your employees to continue their exchanges via chat, rather than email.

As we are increasingly involved in sustainability initiatives, our priority in 2023 is to develop even more green IT functionality.

Frequently asked questions

1

Troubleshooting: Thunderbird Email Signature Image Not Showing

If your thunderbird email signature image not showing, check these common issues:

  • Ensure images are hosted online with accessible URLs
  • Verify HTML code syntax is correct
  • Check that image dimensions are appropriate for email clients
  • Confirm the image format is supported (PNG, JPG)
  • Test with different email clients to ensure compatibility
2

Email Signature Generator Thunderbird Compatibility

Many email signature generators create signatures compatible with this email client. These tools help generate HTML code that works seamlessly with Thunderbird's signature settings, allowing you to include social media icons, logos, and formatted text without manual coding.

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Looking for a tool to manage your email signatures?

Letsignit allows you to create, manage, and deploy email signatures for all your employees in just a few clicks.
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