Pruning will definitely help, but it only solves half the problem. Stretching out is a signal of insufficient light, and if you just cut off the top without moving it to a brighter spot, the plant will keep stretching. So first move your jade plant to a window with maximum light (preferably south- or west-facing), and then do the pruning. New shoots will grow more compactly with proper light.
You can do a few things with the cutting. Rooting in water works fast - put the cut in a glass, and roots will appear in a couple of weeks. Then transplant it into soil. If you prefer to go straight into soil, use a mix of sand and soil (about 1:1) and keep it slightly moist at first. The main thing is don't overwater: your jade plant can rot in moist soil after cutting.
Here's a life hack people often forget: the stump left after pruning will produce side shoots, and you'll get a bushy plant. But if there's not enough light, even those shoots will be sparse. So good lighting is the foundation for everything else.