How to setup a signature block in RoundcubeIn Roundcube, select settings (The gear):
Click on Identities on the first column and select your email address on the right:
You will see the signature block at the bottom of the left screen:
Please do the following:
1. Check HTML Signature
2. Insert your signature, as you want it in the block
You will note that when you hit enter it adds a blank line, use CTRL-ENTER to add a single line.
There are several buttons on the editor that allow you to change colors, add links and images.