unless the title is husband OR wife but to be on the safe side both should sign. also if there are two names and one is deceased get a copy of death cert to cover your butt.
Disclaimer.... I'm not a legal expert by any means and don't want to scare you, I'm originally from CA and have "Cover Thy Butt" firmly ingrained into me. And if this is the first time you have bought a car from a privet party call the DMV or AAA or the like and get some state specific advice. You can also call the local PD non emergency number and ask if they will run the vin and license plate to see if there is anything wrong with the car legally.
So excited for you.
Have fun.
