There are 13 qualifying tournaments players can choose to participate in with hopes of earning a place at the US Open, but the majority of spots go to professional tennis players who are ranked internationally.
There are also eight “wild card” spots in each tournament, which are given out at the discretion of the organizers. These are often reserved for players who have won a notable tournament, who have finished as runners-up at multiple tournaments, or perhaps for those pros who have stepped away a bit but want to end their career with one more go at the US Open.