Hi Jonsturm34,
This would depend on if the e-mail template that you are using is your own created from scratch or based on one of our stock templates. If the e-mail template is from one of our stock templates then you can use the Merge Fields feature to pull in your signature easily by using Users.EmailSignature. If your e-mail template is customized based on a customized screen than you will need to ensure the screen has the appropiate character functions setup in order to have the merged fields option work.
You can refer to one of our stock Email templates for reference for example the Case Update to Contact template based on the CRM_EditCase screen.
The above scenario is if you are actually using a template, additionally please note that you do not need to use a template to make this work, you can manually type in Users.EmailSignature into the body of the e-mail given the screen it is based on has the appropiate character function.
You can view our help center article on merged fields below which can further aide you :
Merge Fields
- Sam