Well, that's an interesting question. The answer will depend upon what state you reside in and that state's licensing laws.
In my state (TX) anyone who's over the age of 18 can apply for a full, unrestricted driver's license at any time, and there's no special "permit" or "waiting period" required.
You take proof of identity and age (a birth certificate) and go down to your local DMV licensing office.
Pay the application fee and take and pass the vision exam and the written test. Then, you make an appointment to take the road test.
You have to pass the written test before you'll be allowed to take the road test. Passing the written test becomes your "permit" (so to speak) or authorization to take the road test. If you pass the road test, you'll be issued a full, unrestricted driver's license.
At some of the larger DMV offices in the state, all this can be accomplished on the same day. Again, that's the licensing requirements in MY state - your state's requirements may be different. Phone your local DMV office and ask them.