First, welcome to the forum markayla12.
Let me start by saying there is only one true pitbull and that is the American Pitbull Terrier. Being terriers they are not large dogs. Many range from 35-50 pounds. So, when you see these large 75 pound and up pitbulls advertised they are mixed breed dogs or mutts.
If you truly want an APBT
you need to purchase from a reputable dealer. With Covid going on dog shows may be limited but look in your surrounding area for APBT
shows and competitions. Going to these is a great way to find the bloodline you like and to get to know some of the breeders.
Do some research, if you haven't, on the breed and decide if it is the right dog for your personality and life style. These are high energy dogs and require a lot of mental and physical exercise. You must be willing and have the availability to provide this.
If you can provide where you live perhaps someone can recommend a breeder in your area. Just be careful as there are many backyard breeders that are selling mutts that are not health checked and will take your money and run. Good luck.