How can character data like XP and money be stored to be used in a store on the main menu not inside the story mode of the game?

You should store it inside PlayerState, so they would be accessible from any pawn. However, if you want them to pass from map to map, override function of PlayerState, which named CopyProperties. Good luck!

would the information be accessible to use for like a store that is not available while in game. It would have its own button on the Main Menu?
Thanks!

No, I didn’t understand what you want properly, but now I get it. You can create child Blueprint from SaveGameObject then create variables inside it and save it to the slot using its ready functions. It would be saved into file and you can load it everywhere you want.

How can character data like XP and money be stored to be used in a store on the main menu ;not inside the story mode of the game?
Thanks.

Did you try this?