What type of refrigerant goes in 1994 Mazda b 3000 pick up?

It should be R134a the fittings high and low pressure line should be large in size.Your model year should have a sticker under the hood unless it is gone stating this.The early 90s stuff like yours should be the newer air condition product.Any local shop can point this out and even the air condition compressor may have a decal stating the refrigerant that should be used.