There isn't a single "fill plug" for the entire A/C system on a 1994 Chevy Beretta (or any car). The A/C system uses refrigerant, and adding refrigerant requires accessing specific ports on the components, usually the low-pressure side. These are usually accessed with specialized tools and gauges.
You should not attempt to add refrigerant yourself unless you are a trained A/C technician.
Improperly adding refrigerant can damage the compressor and other components, leading to expensive repairs.
To recharge your A/C system, take your 1994 Chevy Beretta to a qualified automotive A/C technician. They have the proper equipment, knowledge, and safety precautions to diagnose and repair your system correctly.
