How do I Upgrade features in game and implementing them

Very brand new to all this, basically put I’ve learned how to create an endless runner type 2D and do all the level design to include power ups. My next step is to implement upgrades / unlocks in the game. The question is how do I make it so once someone were to say use coins or an in app purchase to unlock something, actually unlock it for them and upgrade the current feature in game? Hope that’s not too confusing of a question, if anyone has any resource links they can pass my way that will help as well.

The system necessary to have permanent unlocks that persist between game sessions would likely be different from unlocks that only last as long as one game session.

If you want the player to be able to hold on to a power up until they leave the game / change levels / die, then you need only store some information somewhere on some long-lasting class or blueprint in your game that signals to wherever you need the information that the unlock has been acquired. For instance, if you have a blueprint that represents your character, and there are four possible unlocks, you’d have four boolean variables (or an array of length 4) where each is used to determine if the player has unlocked that one yet.

If you want a permanent list of unlocks that lasts even after the player exits the game, then you could probably use the Save game feature in Unreal. Saving and Loading Your Game | Unreal Engine Documentation