Each fence style has its own conforming gate choices. There are single walk through gates and double drive thru gates. For most styles there are pre-assembled gates in one or more common sizes that are put together at the factory ( usually the best value) and there are gate kits available that can be custom sized to fit a pre-existing opening at the job site. The largest single swing gate available in a residential style is generally 72” or 6 ft. (some styles have more limited choices) The largest Drive Thru gate is therefore 12 ft +and the smallest single gate can be made on site with the gate kit.
Gates require separate hinges and latches plus Gate Post Stiffeners for each gate. Double/Drive Thru gates usually require a drop pin kit to secure one gate to the ground so the other one can latch to it.