It's pretty easy for most "car guys", but I removed the mudflap and thought I would post some photos incase someone else was searching for it. The mudflap is attached to a metal bracket support that is attached to the frame of the truck. Unscrew that support. Mine started to unscrew and then broke off due to the rust on my truck. I used an 8mm socket.
The second place the mudflap is attached is behind the plastic flare with what I think is called a "christmas tree screw"? I could be wrong about that but it is the kind of screw that goes in easy, but is hard to pull out. It is also plastic. Tugging, wiggling, and using a flat head screw driver to get some leverage snapped it right out.
The rubbing stopped except for a very specific angle, at slow speed, in the front driver side. There is a small part of the bumper that hooks back under the truck that will occasionally hit it. It does not happen on the passenger side. It is rare and "OK" for now. On my list of improvements is a black front bumper that works with existing tow hooks. Changing the bumper will probably correct the issue.