You can add a text signature that will appear at the bottom of all incoming/outgoing emails. This doesn't include html signatures or images. Please use a mail program like Thunderbird to create that.
Step 1
Login to your webmail account. If you need assistance consult the tutorial How to Access Webmail.

Step 2
Select the "Settings" tab from the upper navigation menu. It will open the Settings>Mail page.

Step 3
Select the "Identities" from the left-hand column.

Step 4
Next select the account you want to create a signature for. The signature settings will appear and you can customize your account. You can create a new signature by clicking the + Create button. Select default Reply to and Copy options, and set the signature as your default for all messages. Once you have updated the settings click "Save". Now when you go to compose your signature will automatically be added to emails.
