Joanna T.
I would have it all on categories in a binder for important stuff like bills and documents that you need to hold onto, medical and work papers included, just put the letters or envelopes in the plastic sheets and maybe date them based on when they arrived or when you need to deal with them by. If you pay certain bills and try to save money for it, keeping the money in the folder within the same section may also help keep track of how much you have. If not a folder, then something more simple like a box or simply a drawer where you can keep them in categories and in order should do, it just depends on the level of organisation you want.
Keyra N.
Seperate them in different boxes, you can choose the colors for example : Any economic stuff is in the green box, any medical stuff is in the blue box and any personal stuff in the red box.