You need five grand soul gems with a grand soul and you need access to an enchanting altar. Lastly you need five piece to enchant (ex. two ring, a necklace, dark shirt and pants).

Skills/spells: you need to have an illusion high enough to use chameleon, then enchant each item with chemeleon. Each item will have 20-24% chameleon. With all five being worn you have 100% chameleon so now you can interact with stuff and be completely invisible.

Note: I don't know if this still works after certain updates. Please comment if you find out.