First, it's usually R-22 which can't be sold to an unlicensed tech.

Second, refrigerators usually don't have service valves on them. You
have to buy clamp on piercing valves.

Third, a refrigerator is a sealed system. If it's low on refrigerant,
it's because you have a leak. If you don't fix the leak and keep
adding refrigerant, you'll end up diluting the oil and burning up the
compressor.

Does anyone know how to recharge whirlpool gd5nhgxkq01 refrigerator?
or have a service manual?

What type freon do these units take...r134a, r12, r22, etc?