99 f350 sloppy steering

You can tighten the steering box, on the driver's side you'll see the top of the box, a lock nut and an allen key. First you unlock the nut, then you turn clockwise to tighten it. However, there may be another underlying problem here, such as worn front end parts (ball joints, tie rods, etc). I would check those first, and use the adjustment as a last resort if everything else checks out.