Steering seems to be binding

All vehicles have a safety feature that won't allow a vehicle to be shifted into gear without the drivers foot being on the brake pedal . Shifter interlock system . There is a electrically controlled solenoid that locks the shifter ,when you step on the brake pedal an electrical signal un locks the shifter ,allowing the gear selector to move.

Either the "key lock " is broken, or you have the wrong key, or the steering wheel is in a bind.
Usually, the problem is # 3.
To fix it, either you or someone else needs to pull the steering wheel to the right or left until the key will turn.
One person pulls the wheel right of left whilst the other tries to turn the ignition key.
Do not force the key, but it is OK to tug the steering wheel.
This might take a little muscle.
If your front wheel is up against a curb, or something, this can happen.
God bless your efforts.

If the steering wheel was in a hard turn when the ignition was turned off and the key was pulled, maybe it's just in a bind. Put the key in the ignition and pull the steering wheel hard to the left, then to the right while trying to turn the ignition.

Unless the vehicle has just a tremendous amount of sloppiness in the steering wheel or the ignition switch. It may just be in a bind and need a little more pressure than normal to allow you to unlock it. It may even take the help of a friend if it's in a bind or the steering is locked with the wheels turned severely one direction or the other. Have a friend grab the steering wheel and pull it down hard to the left or right while you try to turn the key. I mean a hard steady pull, not a quick ****. If it still doesn't release you most likely have an internal problem with the locking mechanism or the ignition switch itself.

the ignitio switc tumblers are worn out and you need to replace the switch

This sounds like textbook steering rack failure. If the internal seals wear out the rack will leak fluid internally, causing the exact symptoms you're describing. These can be rebuilt, but it's hardly worth the effort. It's less headache and only slightly more expensive to replace it.

I would try and nudge the steering wheel around a little first. Sometimes the steering wheel can be in a bind and prevent the ignition lock from turning. Try and turn it to the left/right and/or push down/pull up on the wheel.

Thank you for your question, please let me know what happens.

-Mike

No adjustment, sound like gearbox has failed, be sure to flush power steering system before installing new gearbox.

Have you checked the U-joints in the front axle for the 4X4? If those U-joints are are tying up they will affect the steering. Good luck!

Check the tie rod, tie rod ends, and ball joints for excessive play. Jack up the front on either side and have a helper push and pull on the top or bottom of the tire. Watch the area where the hub pivots on the axle. if both sides check out. with the truck on the ground, have the helper turn the steeribg wheel back and forth about a half turn with the key off. Look for loose outer tie rod ends, and inner tie rod ends.
F-250 4x4 steering componants are pretty basic, If your unsure what to look for then take it to someone that knows how to fix it. Correctly. If you replaced any of the joints. It would be in your best interest to get it alighned.