If ur under 18 can the parent or guardian sign for an apartment but not live in it with the child?

It is legally possible since the adult is executing the contract, but it will be hard to find a landlord that will rent a place this way. They won't care that they will be able to hold the adult responsible for any damages or charges or "issues"; they will not want to deal with it. And they will be able to turn you down without fear of violating any anti-discrimination statutes.