It is up to their respective Football Federation (Spain: RFEF, England: FA, Germany: DFB, etc.), but FIFA pays each Federation a bonus: https://intereconomia.com/wp-content/uploads/2026/07/image-2...

In the average country players agree the bonus conditions with their Federation.

FIFA pays federations on a result basis. It's then up to the individual federations to redistribute that money as you see fit. As you can imagine, a lot of that does not end up in the athletes' pockets... I believe clubs get some (low) compensation for injuries, but it's also common knowledge that players who play deep into summer will end up performing poorly the following season.