Email signatures in Gorgias can be customized for each email integration. To set up an email signature, you will go to Settings, Integrations, Email. Then click on the email integration that you want to start with. In the signature box, you can enter any text you want to appear on all agents signatures for this particular email integration. By selecting the "Current agent" drop down (image below) you can input variables such as "Current agent first name" which will automatically insert the current agents first name into the signature on the ticket.
Once you have set up your signature select "Save changes". When you are in an email ticket, your signature will automatically be sent at the bottom of the text. To view your signature in the message select the icon on the bottom left of the text box as shown below.