Hey @Arnthem, welcome to the forum community!
Unreal has a built in way to take in-game screenshots! You can specify the default path yourself too, to be able to access the files later!
You could also take a high-resolution screenshot - but this may increase the storage size of the game without some restrictions.
Community Hero Rama has a Victory plugin for help though, if you want something that’s really easy!
I hope this can help!
-Zen 