The handle for lowering the spare tire on a 1998 Ford F-150 is usually located
inside the rear cargo area, on the driver's side. It's often a small, relatively inconspicuous pull-handle or lever, sometimes near the wheel well or on the sidewall.
However, the exact location can vary slightly depending on the specific trim level and whether any aftermarket modifications have been made. If you can't find it easily, check your owner's manual – it should have a diagram showing its location.