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
The following steps are needed to create or change a signature in the Horde WebMail:
- 
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."