How to add a signature to your emails
 

Webmail

Instructions from Microsoft site

Thunderbird

Click on your email address at the top of the left-hand menu, then "View settings for this account". Either type your signature or tick the box to attach it from a file and browse for the file. Click OK to save your settings.

Pine and mutt

Create a file called .signature in your home directory and pine and mutt will include it in your emails automatically.