Have a situation where an unmarried couple r living together. One decides to move out & is not owner or part owner of home. Address on lics and car regis is the home moving out of. Can that person return to the home for personal items like the car, clothes, computer etc? No legal documents like pfa or restraining order apply. This is in Pennsylvania. Thank you first time asker!!

Yes ; you may retrieve your personal belongings from the property. Also immediately notify your local post office of your new address so your mail can be forwarded. Actually this can be done online. If the owner/remaining occupant of the property will not give you access for the purpose of gathering your personal belongings then you may be able to enlist the aid of your local police department in the interest of doing it as peacefully and quickly as possible.

Be sure to go down to the DMV and have your driver's license and car registration changed and you get brand new d/l and registration. Just sending them written notice sometimes slips through the cracks.

I certainly would not want anything from the state coming to the old address even if you do change your address with post office.

Yes, but they need to get their things now, ASAP, remember the other person will most likely change the locks and so on very shortly.
You can not break in, but would have to have the other perosn let you in.