Payload and towing capacity are different limits
Payload is the weight the vehicle itself can carry: people, cargo and the downward weight of the trailer on the hitch. Towing capacity is the weight of the trailer it can pull. Both apply at the same time, and payload often runs out first.
What counts as payload
Ford defines payload as the combined maximum allowable weight of cargo and passengers the vehicle is designed to carry: the gross vehicle weight rating (GVWR) minus the base curb weight.
The same guide says that when towing, the trailer's tongue load or king pin weight is part of the cargo weight. So the part of the trailer that presses down on the hitch uses up payload, along with everyone and everything in the truck.
Where the limit for your vehicle is printed
The GVWR is on the safety compliance label on the driver's door edge or door pillar, with the axle ratings. That label is for your vehicle as built, which is why it is the number to trust over any table.
Our tables are about trailer weight. Payload varies with every option fitted, so manufacturers publish it as a maximum or a range, and the real figure for your truck is the one on its own label.
This explains the terms. The limits for your own vehicle are on its door-jamb label and in its owner's manual.