I have a 1985 Ford F-150 so my starter will spin but won’t engage what would be my problem

Like Moab noted in the comments, that means that you need a new starter. Thankfully those aren't too hard to replace, especially on a car (truck) of that age.

If the starter motor spins, but doesn't crank the engine, the solenoid (bump on top of the starter) is bad—that's what pulls the starter gear into contact with the teeth on the flywheel or flex plate. Could replace starter ($50-100 part) or solenoid ($10-20 part). Easier to replace entire starter, cheaper to replace just the solenoid.