There are three ways to use pressure points combatively.
First is “Pressure point fighting” which is to activate a single point on the body to achieve a desired effect… usually pain.
The second is Tuite, which is the activation of specific points to release the muscles and tendons which support the joints of the body so they become easier to lock or break.
The third and most advance use of pressure points is Kyusho Jitsu, using points to overload the bodies nervous system causing unconsciousness.
Each “advanced” level builds on the others, but all contain elements of each. This is to say, there are single points that may cause a knock out (PPF) but they work much better if you set them up first with other points (Kyusho Jitsu), which just may involve a joint lock (Tuite).