Yes, it’s possible to add clothing washer/dryer hookups if you don’t already have them. You need electric, hot + cold water, and a drain.
If you don’t have factory hookups then you need to build them. I haven’t done it, but I have re-plumbed my existing hookups and I’m convinced it isn’t a very difficult task. You need a drain and then hot and cold water lines.
Hot and cold water which is easy- just tap into any line under the camper. Cut it, install a “T” with Sharkbite fittings, and then run water to where you need it.
Then you need a 1 1/2” drain. Again, drop down into the under belly, add a p-trap. Now you need to decide if you’re going to share the existing sewer outlet or if you’ll add a new one. Reusing the existing one means cutting off what’s there so that you can run a pipe into it. Adding a new one means you need to step up to a standard 3” sewer connection.
Finally, you need a vent. There are standard vent kits. It’s cutting that 4″ hole that makes people get panicky.
It sounds like a lot of work but it’s really not terrible. I replumbed my combo washer/dryer in our garage because it was going to a black tank. I added a diverter valve so I can either dump it straight to the sewer or to the existing black tank.