A signature adds several lines of text automatically to your email. Usually this is your company and contact information. In order to create a signature in Zimbra, open your account and choose preferences. When you open preferences you will see the signature tab. Select the tab.
When the signature tab opens, choose Edit and you can create your signature.
Enter the information for your signature. You can format as plain text or HTML.
Provide a name for your signature and select "Done"
Once you have created a signature you can see that "Add Signature" is available to add a second or third signature.
This will allow you to use different signatures for different clients or friends.
If you want to make the signature permanent then choose "Preferences" and "Signature". Below your signature you will see the "Using Signatures" and now select the "Accounts Page" which will allow you to make it permanent.
Change the "Do Not Attach Signature" to the signature of your choice.