1986 ford bronco 2 won't start turn the key just clicks doesn't crank just clicks now it don't do that answers please

Check the battery for a full charge .

Right, sounds like the battery.

Install a new battery, clean the battery terminals, and clean the cable connections. It's best to have the auto parts store charge the new battery, prior to installation--it saves your alternator. Alternators are battery maintainers, not chargers.