How to add an email signature in Thunderbird

Thunderbird is a free and open source email application created by Mozilla. It is easy to use and make it really easy to manage your email signature.

By default the signature editor in Thunderbird only allows plain text, or advanced HTML. If you want to make something more advanced, we would recommend using a tool like our email signature generator. This tool allows you to choose from a set of starting templates and customize them by changing fonts, colors, images and adding additional fields. It creates the HTML code for you so you don't even have to worry about it!

Here is a step by step process of how to add your email signature to Mozilla Thunderbird. This guide assumes you have already copied your email signature to your clipboard using an editor like, from an email, or from another source.

  1. Open the Thunderbird Desktop application on your PC or Mac. Click on the three bars menu icon near the top right. Then click on Account Settings.

    add signature to Mozilla Thunderbird step 1

  2. Once in the Account Settings menu, on the left sidebar make sure that you click on your account name. Typically your email address.

    add signature to Mozilla Thunderbird step 2

  3. In the right column, under Default Identity look for Signature Text. This is where you can edit your signature. Check the box for Use HTML.

    add signature to Mozilla Thunderbird step 3

  4. Paste your signature into the textarea under Signature Text. It will show up as HTML code. This is what it is supposed to do! There is no need to click save.

    add signature to Mozilla Thunderbird step 4

  5. When you start a new email, you will now see your signature at the bottom of that email.

    Don't worry about the red borders around your signature! Thunderbird is trying to show you, the editor of the email, the underlying structure of the HTML table code. When the email is sent it will not show up for the receiver of the email. If you don't trust me send an email to yourself! To our knowledge, there is not an easy way to turn off this functionality.

    add signature to Mozilla Thunderbird step 5

That's it, you are finished! You are now a pro at managing signatures in the Thunderbird email client. If you have additional questions please don’t hesitate to reach out and let me know! You may also want to check out my beginners guide on creating email signatures.

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