Don't worry about having to type your email signature over and over again on each email. Follow the steps below to customize your email signature:
1. Click on the profile icon on the top right corner of your screen and select Email Settings:

2. Click on the Email Signature and create your signature. You can also format your signature and make it "jazzy" if you want to:

3. Once you're happy with your edits, click on the Save Button!
Here's a short video to help you do this:
Hope this helped!