Just an FYI, if what you are asking about is how to recover someone that is stuck in a ditch, make sure that you buy a "Recovery strap", which does NOT have the metal hooks on the end. A "Tow Strap" has metal hooks, and isn't designed to stretch. Many people have been injured or killed by having one of those hooks come loose and rocket straight back at them.
If you are talking about towing another vehicle for a long distance, then you can either do trailer or flat tow, depending on the vehicle. If you trailer, then make sure that you get a flatbed with trailer brakes, and get a brake controller for the 4R. Any trailer weight over 2000 to 3000 lbs should have brakes. If you are flat towing, you can also get controllers that will actuate the tow'ed vehicle's brakes. Also, with flat towing, the tow bar should be level or at a slight up angle to the tow vehicle. If not, the tow'ed vehicle will try to crawl up over the tow vehicle in hard braking.
--Mike