Hi,
The XP or experience points is a way to measure your achievements in Microsoft Learn, each module of each learning path gives a certain amount of XP which can be seen in beforehand.
If you want to know more, I suggest you ask in the dedicated Microsoft Learn forum over here:
https://trainingsupport.microsoft.com/en-us/tcml/forum
For the reputation points in Microsoft Q&A there are some details here:
https://video2.skills-academy.com/en-us/answers/articles/374/reputation-points.html
(Please don't forget to accept helpful replies as answer)
Best regards,
Leon