How do I edit my signature and is it possible to edit a post "title"

 

Your signature is edited via the 'User CP' link in the header bar below the site banner. Click on 'User CP', then scroll down looking at the side bar until you find 'Edit Signature'.

As far as changing thread titles goes, that is something that the staff can do if you need it to be done. It isn't a usual occurrence.

*Moving to Website Problems & Suggestions*