what type of refrigerant liquid would i buy for a 1999 buick lesabre custom? on 1999 Buick Century

My A.C wont blow out cold air and i want to know how to fix it.

2 answers
SEEK DIAG AND EST TO SAVE TIME AND MONEY
If you need to top it up you have a leak, you need a tech to look at it.
It's more then likely 134 refrigerant if you do try to do it you self which I recommend not to.
Buy the refrigerant with dye so you can see we're the
Leak is