Roundcube 
The free webmail client RoundCube allows you to set up a signature for outgoing messages. 

• Click on "Settings" at the top right side of the page.
• On the Settings page, click on the "Identities" Tab.
• Double click on the email address that you want to create a signature for.
• Click on "Settings" at the top right side of the page.
• On the Settings page, click on the "Identities" Tab.
• Double click on the email address that you want to create a signature for.
• Add your signature.

SquirrelMail 
To have a signature on all of your outgoing emails, you can add one in SquirrelMail in the Personal Information section. 

• First, log into your SquirrelMail.
• Click on Options at the top of the screen.
• Click on "Personal Information."
• On the next screen you will be able to insert your signature.

Horde
You may create or change a signature in the Horde WebMail following the steps given below:

• On the icon bar at the very top of any mail page in the Horde WebMail application, click on the options icon, then on Preferences.
• In the Your Information column, click Personal Information.
• On the Personal Information page, click Edit Your Identities.
• Select the Default identity from the Your Identities pop-up menu, type your signature text, and click the Create button.
• Confirmation that the change you have made to your default identity will appear at the top of your window stating "adding a signature file."