Email signatures are a powerful tool offered by Thunderbird, heavily used by businesses and working professionals to maintain brand identity, build credibility, and provide all the necessary contact details to the recipient.
An email signature may comprise Plain Text, HTML, images, and even links. In most cases, when creating a signature in Thunderbird, a user includes: Name, Designation, Contact Number, Address, and Logo, etc.
How to Create and Add a Plain Text Signature in Thunderbird?
Note: In Thunderbird, you can set up different signatures for each configured email account.
Plain text is the simplest signature that you can use in Thunderbird, and the easiest to set up:
- Open Mozilla Thunderbird.
- Go to the Navigation Menu (three lines on top right).
- Choose Account Settings.
- Go to the Default Identity >> Signature Text section.
- Customise the text you want to enter in the signature.

Add Signature in Thunderbird with HTML Formatting
Mozilla Thunderbird, as an email client, enables you to use HTML(Hypertext Markup Language) to add basic formatting to your signature. Set up an email signature in Thunderbird with HTML, and give a more professional look to your email signature.
- Go to Thunderbird >> Account Settings >> Default Identity.
- Check the “Use HTML (e.g., <b>bold</b>)” box under signature.
- Enter your HTML signature code and press Ok.

Tip: There are multiple HTML formats available on the internet that you can use to create a signature.
Verify if your signature has been added successfully:
- Go to “Mail” in Thunderbird.
- Click on New Message.
- You can now view your setup signature.

Set up Email Signature in Thunderbird with a File or an Image
Thunderbird supports .txt, .html, and images in .png, .jpeg, and .gif format.
Important: You can either add a signature Text or a Signature file in Mozilla Thunderbird. You cannot add both at once.
- Open Thunderbird >> Account Settings >> Default Identity.
- Scroll down to “Signature.”
- Check the “Attach the signature from a file instead (text, HTML, or image)” box.

- Choose the image, logo, or HTML file signature and press Open.

How to Add Signature in Thunderbird for Reply?
With the default creation of an email signature in Mozilla Thunderbird, it is only enabled for the “New Message.”
Follow the steps to set up a signature in Thunderbird for replies and forwards:
- Go to Thunderbird >> Navigation Menu.
- Navigate to the “Account Settings” section.
- Scroll to “Composition & Addressing.”
- Check the “Include Signature for Replies” & “Include Signature for Forwards” options.

- You may need to restart Thunderbird after this.
Change an Email Signature in Thunderbird for Mac or Windows
You can edit the signature at the default level or even at the individual message level.
Steps to modify Thunderbird at the account level:
- Select Navigation Menu.
- Select Accounts Settings > Signatures.
- Edit the content in the signature box
- After making your changes, select Save.
To modify the file-based signature:
- Open the original file.
- Make the desired changes.
- Go to the signature section in Account Settings.
- Click on Choose to select the correct file again.
Change Email Signature at Individual Message
- When composing a message in Thunderbird, go to the signature section.
- Make the changes in the visible text.
You can only modify the Text Signature, TXT file, or HTML file email signature at an individual message level.
You can also remove a signature in Thunderbird from an individual message. To do so, select the email signature when composing and delete it.
Keep in mind: You can only remove an image signature and not modify it at the point of New message composition.
FAQs: Add Signature in Thunderbird
Q1: Does Thunderbird have signatures?
Yes, all the latest versions of Thunderbird for Mac or Windows have an option to set up account-level signatures.
Q2: Can I add a signature to all accounts in Mozilla Thunderbird at once?
No, Thunderbird does not offer a global option to add signatures. You have to set them up one at a time.
Q3: How to remove an email signature in Thunderbird?
To remove a file-based signature, uncheck the “Attach the signature from a file instead (text, HTML, or image)” box in account settings. Or clear out the “Signature Text” box if you have added a signature by plain text or manually in HTML.
Q4: Is there any Thunderbird Add-On for managing signatures?
Yes, there are add-ons/extensions for email signature as well, but they sometimes lead to compatibility & performance issues. Using the built-in option to add a signature in Thunderbird is recommended.
We hope you have now successfully learned to modify, remove, or add signatures in Thunderbird.
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