Ford says 12,200 pounds maximum. Your owners manual should confirm that.
That probably means you can tow a trailer with an unloaded (dry) weight of around 10,500 pounds maximum. Don't forget that you will add weight with everything from water and propane to food, clothing, "toys," etc. It is easier than a lot of folks think to add 1,500 pounds to an RV.
If you read the owners manual for the 2016 F150, Page 262 - 269, there is a very thorough discussion of GCWR ( this is combined rating, total weight; truck, belongings and trailer.) Depending on the truck configuration, 4x2, 4x4, extended cab, etc. the ratings are all there.
If you going to pull a 5th wheel that weighs in at 12,200 about 20% to 25% of that weight going to be in the back of your truck which is between 2400 and 3050 just for the pin weight.
If you going to pull a pull behind you going to put between 10% and 15% on the back of your truck or between 1220 and 1464. The problem with that is the hitch has a sticker on it that only rated to around 1200 pounds.
Here is a site that you can figure what YOUR truck to tow by using the numbers assigned to your truck that is listed on the yellow tag on the door jam of your truck. Don't use web specs.
Once You figure all the weight out, aerodynamics will play a big part in towing comfort. i Had a F150 towing a 30ft pull camper and it towed like a dog. I was at max weight and although it was suppose to pull fine the aero drag was terrible. I designed a wind deflector that I put on the campershell of the truck and towed with that. Wow it gave me about 2-3 miles per gal savings and I could actually have power going down the interstate.