So this forum is a little dizzy right? A lot of stuff cant be changed in admin settings so Ill guide you through how to use signatures.
a. Create signature with text, or images - 500 characters max.
1. Go to Profile
2. Select Preferences
3. Place "Yes" at "Always attach signature"
4. Done (signatures will ONLY appear on new posts when you post after the signature option has been set to yet.