How can a tennis player participate in the Grand slam?

(this question has two possible meanings; both are responded to, below)

(1) To sign-up for tickets for a Grand Slam event, spectators must contact the venue's ticket office, or buy tickets from a legitimate reseller, some of which may be found online. Some Grand Slam events give past ticket holders a chance to buy tickets for the following season(s). Some events, such as Wimbledon, sell a limited number of "debentures" (i.e., very expensive stocks, which, in this case, are traded on the London (Stock) Market) to anyone who can afford it, but there are strict limitations to owning such debentures.

(2) Professional tennis players may sign-up for a Grand Slam event by requesting a "bye", seeding, or entry into the event, usually through their agent or manager. Since Grand Slam events only have room for 128 players in the men's and women's singles, only a limited number can play.