Can a finance company copy and paste your signature of a Notice of vechicle credit application and paste it on a new document that i didnt authorize
Not without your authorization. That would be forgery (and maybe fraud depending on the circumstances.)
Car dealers do this all the time. Until they get caught at it. It makes the contract void for the forgery. I would suggest getting a copy of the documents and then hire an attorney who can have a handwriting expert look at the documents to establish yoru case.
Good luck
This is why I won't sign on those little electronic terminals at retail stores.