How to install your email signature in Thunderbird
Thunderbird wants the signature's HTML source, not a rich paste. Turn on Use HTML in your account's signature settings, then paste the copied HTML source into the box. Thunderbird renders it into the formatted signature. If your signature is image heavy, attaching it as an .html file is even more reliable. Either way takes about two minutes.
Do not have a signature to install yet? Build one free, no signup.
Open the generatorCopy the HTML source
Open your personal signature link, pick Thunderbird from the client dropdown, and click Copy HTML source. This copies the raw HTML text, which is what Thunderbird's HTML signature box expects.
Open your account's signature settings
In Thunderbird, click your email account name in the left folder pane, then choose Account Settings (or Manage account, View settings for this account).
Turn on Use HTML
Scroll to the Signature text section and check the box labeled Use HTML (so the following text will not be interpreted as plain text).
Paste the source and save
Click into the signature box and paste (Ctrl+V). Click OK to save. Thunderbird converts the HTML source into your formatted signature.
Image heavy? Attach it as a file instead
For signatures with several images, use Download .htm on your personal link, save the file, then check Attach the signature from a file instead and point it at the saved .html file. This tends to survive complex markup better.
Common questions
Thunderbird's signature box, with Use HTML checked, interprets what you paste as HTML source. Pasting the raw HTML text is the reliable path; a plain visual copy can lose structure. The client dropdown on your personal link switches the Copy button to give you the source directly.
Yes. If Use HTML is unchecked while the box contains HTML tags, Thunderbird sends the literal tags as visible text instead of rendering them. The checkbox state has to match the content.
Yes, the images are hosted on our asset domain and referenced by absolute URL, so they load in sent mail. For very image heavy signatures, the attach-as-a-file method is the most robust.