Saving Editor Stuff in Play Mode

Hi there, is there an easy way to change a variable in play mode using a custom in game UI and when you click the save button in your UI it updates and saves the new variable then you exit play mode and it changes to the new variable?

Trying to make an in game developers menu because the play mode is fullscreen so you can't edit variables easy.

Thanks :D

@Loius @Bunny83 @Eric5h5 @robertbu @fafase @programmrzinc