In Pa, tire inspection including correct size, depth etc, suspension check, ball joints tie rods etc, no leaky shocks. Headlights for correct aim and all exterior lights are to be working, turn signals and 4 ways including fog lights if equipped. Brakes are checked for minimum depth. Exhaust for leaks and rust and modifications. Horn and wipers must be working . Rust on vehicle depending on severity will not be passed. No visible fuel leaks or fuel smells. The list goes on and I doubt depending on where you go that all is checked 100 percent but it is required.
Also required is a road test but I have only 1 place ever do that, most places consider the road test when they pull it in the garage
Windshield cracks are iffy depending on location. There is a lot more, the inspection book is about 3/4 inch thick due to different scenarios and all are done by private shops. State does not do inspections BUT they do come out and inspect the stations and also check their books. Once again I don't think everyone follows this but who knows.
Years ago it was done 2x a year but since then changed to once a year.