How to change the oil pan on a 1993 ford E150 van with a 5.8 L

Not sure that model, but most can be removed by: Draining oil, remove all bolts, Some require unbolting Motor Mounts and engine Jacked up to get pan around the Oil Pump.
I would purchase, or go to your Library for the Service Manual. Can save a lot of unnecessary work.

Not sure if you will have enough clearance with the E-series. You may have to remove the upper intake plenum to gain some additional space.

On F-series of this vintage, we used to disconnect the exhaust, remove the bolt for the p/s pressure line @ frame. Remove engine mount bolts and raise the engine up as far as it will go. When you have lowered the pan a couple of inches, you will have to loosen the oil pump bolts in order to clear the oil pan. Its not a fun job even when you are standing under a hoist. If you are attempting this repair while laying on your back, good luck.

It can be changed without removing upper plenum. You need to remove both motor mounts and jack up as high as it will go. Un bolt the pan then un bolt the oil pump pickup. Then you can weasel it out. Not a fun job to say the least. If you don't have access to a hoist don't waste your time trying. If it just needs a new gasket you can change it without pulling the pan completely out. Drop pan as far down as you can then snake olg gasket out and new one in.