If your truck has the factory 7 pin harness with a round plug above the spare tire, all you need is something like this:
https://www.etrailer.com/Custom-Fit-...id=20031310944
If your trailer has electric brakes, you need a controller. I bought a Curt Triflex, but there are many like it. Tekonsha appears to be the most popular. Mine is a proportional controller instead of time delay, basically it applies the brakes as needed to match the tow vehicle instead of applying to a preset tension. Infinitely smoother stops this way. You can hardwire it yourself or get an adapter harness to plug into the distribution panel under the dash. Mine came with the adapter harness.
https://www.etrailer.com/multi-produ...7874&hunter=bc
It has 4 wires: red, blue, black, and white. On mine, black is 12v, white is ground, red is stop lamp signal, and blue is trailer brake control. This is where it gets weird...depending on how your truck was wired from the factory, you may need to run some wire. My underdash panel was pinned for ground and stop lamp signal; however, the trailer brake control wire and power wire were not there. I had to cut the connector harness and run a separate 12v wire to my fuse box under the hood (with a 30 amp fuse inline). When you take off your fuse panel cover, you may have a blue wire dangling there. That is the trailer brake control wire. Run a 10 guage wire from your controller and connect to this wire. If you don't have this wire, you will have to run one to the back to control your brakes.
Hope this helps.