There are two different types of lifts: suspension and body. Though they both change the height and look of your vehicle there are a few key differences.
A body lift kit uses spacers to increase the height of the cabin by separating the suspension from the frame. The body of your vehicle will be higher, but the suspension will be the same height. A body lift has no impact on clearance, but does make it look like your truck got a major boost.
A suspension lift kit will give you more of a noticeable difference and be a good choice if you are looking to take your truck or Jeep off-road. Suspension lift kits can either just space out your factory suspension or replace the suspension with all new parts. You will be able to upgrade to larger tires and add coil overs to help you take on any terrain.
Another popular option is levelling kits, they are not exactly a lift. Levelling kits are used to bring the front of your truck up, making it level with the rear. Some levelling kits also bring the back up slightly in order to level the truck out. Based on the existing suspension in your truck, these kits might include torsion keys, blocks, or leaf springs. Your truck will look like it has a lift kit and be able to fit a larger tire.