Mozilla Thunderbird fully supports HTML email signatures. You just need to switch the signature field to HTML and paste your Mirosign code.
1Create your signature
Design and save your signature in Mirosign (an active subscription is required to copy or download it).
2Open your account signature settings
- In Thunderbird, click your email account name, then View settings for this account (Account Settings).
- Tick the box Use HTML below the Signature text field.
3Paste your signature
- Back in Mirosign, click Copy HTML.
- Paste it into the Signature text box and close Account Settings.
Alternative: instead of pasting, you can tick Attach the signature from a file and point it at the HTML file you downloaded from Mirosign.
Click Write to start a new message and check your signature appears correctly.