I use a lot of pre-hungs, but openings with doors wider than 36" (by-pass and bi-folds) are most commonly bought and installed in the various pieces and parts that make up any door. The door pic and added notes below come from finishcarpentryhelp.com. This is an example of one of the great sites out there that'll walk you through the process of hanging a pre-hung through step-by-step descriptions and videos.
A major feature (and easily taken-for-granted) of the pre-hung door is that the hole for the door hardware has been pre-drilled. However, the knobs won't get popped in just yet, they're a few other things that need to be done first and I typically don't even buy them until just before I am ready to put them all in (Step 34).
When I'm rehabbing an entire house, I like to get all the doors ready and start knocking them out one after the other. I need the same tools and supplies (i.e. - nails and shims) on each door and it's most efficient for me to go from one to the other and get in groove with the task until they're all hung.
As I mentioned above, closet doors have most of the same pieces, but a lot of times the stops are not necessary and the closet parts need to be shopped for and purchased separately. Bi-folds and by-pass doors are examples (as well as pocket doors.)
If you're not highly experienced in interior door work I'll encourage you to take some time to surf around and prep by spending an hour or so reading and watching an instructional video. Don't be too surprised if they make it look easier than it ends up being, but be ready to take your time in the beginning so you can really understand what you're doing at that first one before you build on that experience with the doors that follow your initiation. And, consider reading If Necessary, Just Slow Down.
Jump to Step 29 - Interior Trim