Your bike crank in 1985 has 9/16" x 20 tpi pedal axle threads.

That same era, the clipless pedal was just being introduced and used by some of the pro's, using Look.

Suggest you start out with the Shimano PD-m324. Its a classic platform style on one side with chrome cage, the obverse with SPD.

Plenty of shoes in all styles are available, from conservative to race. The SPD has recessed cleats so walking in them is rather normal.