To change or edit a signature in the ZMT Zimbra Webmailer, the following steps must be followed.
Log in to the ZMT Webmailer
1) Click on the “Preferences” tab at the top,
2) click on “Signatures” on the left-hand side,
3) in the main window, the text field can be used to insert or edit the signature.
To save the changes, click on “Save” at the top left, done.