On the PGA Tour, only the players who make the 36-hole cut each week (except for PGA Tour events where there is no cut) get paid from the PGA Tour prize-money payout of the purse. Players do not get paid if they miss the cut.
However, when we talk about PGA Tour prize money each week, we talk about the prize-money payout based on the PGA Tour 36-hole cut rule, which is down to the top 65 players and ties after two rounds of a tournament. It's the "and ties" part that is tricky in determining just how much money is paid out each week on Tour.
The PGA Tour prize-money distribution table accounts for up to 100 players making the cut at a given tournament. However, when they share what the stated purse is for a given week, it's based on exactly 65 players making the cut. The entire purse is paid out to those hypothetical 65 players who make the 36-hole cut and then complete the tournament.
Most weeks, though, it doesn't work out that cleanly. It's rare to have exactly 65 players make the cut. That means, then, that the PGA Tour owes money to players above and beyond the stated purse.
In an effort to reward PGA Tour players who make the 36-hole cut, the PGA Tour actually adds money to the purse for every player beyond the 65th player to make the cut so that they are compensated for the week. That can mean adding six figures or more to the actual tournament purse, but the payout for those positions is based on the original stated purse, just as is the payout for the top 65 players in the field.
In the events without a cut, every player who completes four rounds of the tournament (or participates fully, in the case of the WGC-Dell Technologies Match Play) is paid and are accounted for in the original stated purse.