How do I remove catalytic converter from my 2000 f150??

Either use a chain type exhaust tubing cutter, or if your real good at making a straight cut a sawzall will also work, you need a straight cut so it will be easier to weld in the replacement unit, this truck will not run properly without a catalyst of some type on it, I would recommend a performance type catalyst as a replacement, they keep back pressure very low and flow quite nicely, combine it with a nice performance muffler or dueling it out with 2 performance mufflers and large tubing and you can have a nice sounding rig plus you might notice an increase in performance and fuel mileage. HTH