Entry lists are often closely tied to the draws and how they are made. While the entry lists are usually announced a few weeks prior to the tournament's start, the draws are made only a few days before the start of the tournament.
Players use their ranking at the time of the entry to enter tournaments, but that ranking is not used when seeds are determined for the draw, as those are based on the ranking when the draw is being made. For example, a player may enter a tournament as the highest-ranked player on the entry list, but they may defend many points in the weeks leading up to the tournament and end up not even among the seeded players.
Number of seeded players in the draws depends on the draw size, and sometimes, those seeded players may also receive a first-round BYE, which means that they are promoted immediately into the second round of the tournament.
In a 128-player draw at a Grand Slam, there are no BYEs awarded to seeded players, and there are 32 seeds at majors. At some of the ATP and WTA 1000 tournaments, there is also a draw with 128 spots, but only 96 of those are occupied by players, giving BYEs to the Top 32 seeds.
At some ATP and WTA 1000 tournaments and also some ATP and WTA 500 events, there is a 64-player draw, with 16 seeds and no BYEs. There is also an alternative with 16 seeds where the Top 8 receive a BYE, and also an alternative with 16 seeds where all 16 receive a first-round BYE.
At most of the ATP and WTA 250 tournaments, there is a 32-player draw, and at many of those, the Top 4 seeded players receive a BYE, sending them into the second round of the tournament.
The draw for a tournament includes all tournament who are eligible to participate in the main draw of the tournament. The vast majority of them qualify via direct entry, but there are also many qualifiers who enter the main draw. Some tournaments make the main draw prior to when the qualifying is finished, the qualifiers are then drawn into "Qualifier / Lucky Loser" spots afterwards, and at others, the draw is made already after the qualifying is finished, putting successful qualifiers into draw spots.
The draws can be also affected by withdrawals of players, especially those that are seeded. How the draw is affected depends on when the withdrawal occurs. In certain cases, the seeded player is replaced by a lucky loser, who, if the seeded player had a BYE, inherits that as well. In other cases, the next highest-ranked player in the draw is promoted into a seeded spot.
