You should be able to hit on the "Edit" and customize the team signature. If not there (due to subscription), you should add your signature in your profile and preferences (Click on name in the top right > Profile & Preferences > Edit Signature).
You should be able to hit on the "Edit" and customize the team signature. If not there (due to subscription), you should add your signature in your profile and preferences (Click on name in the top right > Profile & Preferences > Edit Signature).