Create or Modify Signature File in Thunderbird

Signature is usually the common tailing signed-off text in email. Rather than typing the signature repeatedly, Thunderbird facilitates signature feature to quickly append it. This section guides you on how to create signature file in Thunderbird.

IMPORTANT NOTE Make sure you had set your font before continue.

Preparing Signature

For HTML-format email, one has to prepare the signature file either getting a programmer to write for you or “do it yourself”. The difference is that a programmer can craft a lightweight and percise signature file for you, making your email size a lot lighter, consistent, and percise.

Create Signature “Do-It-Yourself” Style

Alternatively, you can create your the signature on your own until you found your programmer to help you out. To do that, you can compose a new email and design your signature accordingly.

If you need to append a picture, upon pressing insert picture:

  1. Select the image you want to display.
  2. Check Attach this message to the message.
  3. Check Don't use alternative text.
  4. Press OK.

append image into signature composer

Save the Signature File

Once done, you:

  1. Select File > Save As
  2. Select File inside the sub-menu.
  3. Name your signature file. Example: signature_olga.html.
  4. Then save it into your desired directory.


If the signature is composed in html format, it should be saved with the .html extension. Otherwise, you can use .txt extension for text-format email.

save signature composer to file

Modify Signature in the Future

To modify your signature in the future, you can simply just edit the signature file or repeat the DIY create signature process again and overwrite the existing signature file.

Configure Account to Use Signature File

Once done, if you have not do so, you can configure the account to use signature file. To do that, visit the following guide:

Configure Signature File