All golfers are not created equal. One look at the pros tearing it up on the hardest courses in the world and then comparing that to your game should be proof enough. So, what do you do when you have a golf tournament and you want all the players to come in with an equal chance of winning? You handicap the event, so that you don't have to shoot par to play with those who are.
Pick a home club. The USGA considers a club any group or organization of 10 or more members, whether or not there is a golf course affiliated with it. This could be a group of friends by association, those who sign up based on a solicitation, or members of a golf course that has a valid USGA course and slope rating. Essentially a club is licensed by the USGA and is part of the handicap system. The USGA requires that you have a licensed club to turn in your scores and develop your handicap.
Provide proof of identification as well as proof of membership in the golf club in order to start developing a handicap with the USGA. This rule always applies, no matter if your club is an actual golf course or not.
Start scoring your rounds. The USGA wants a minimum of five full rounds to start establishing a handicap. Preferably, you should have 20 rounds under your belt. The technical specifications set forth by the USGA require that you play at least three of your rounds with existing club members, as well as one round in a tournament format. There is no rule stating that your rounds must be played at a specific course, just that they are played on a course with a valid USGA course and slope rating. Rounds played will establish a raw score for 18 holes that you can use for your handicap index.
Post your scores. Scores need to be posted with your home club in order to be submitted with the USGA.
Continue to post scores as you play. You'll want to post these at your home course so that they can continue to adjust your handicap.
Play in a league or tournament. You'll use your handicap and then adjust it according to the course difficulty. Depending on the handicap of who you are playing, they will have to give you strokes or you will have to give them strokes.