There should be a drip pan/tray directly below the coils on the inside of the fridge. This tray goes all the way across under the coils...it looks like a shelf. The tray has a short plastic extended tube that fits into a drain hole directly behind it. (You have to remove the tray to see the hole.)
Sometimes the tray sags and the tube won't line up with the drain hole without a little effort. On the backside of the fridge the drain hole has a plastic tube to take the water to the outside via the vent cover on the outside of the RV.
That tube gets brittle and breaks off. It's easy to replace with tubing from a hardware store.
If the tray is gone or you don't have the time to unplug the drain hole, just put 3 or 4 rolled up paper towels, roll them up like a tube, and put them directly under the coils. It doesn't matter if they touch the coils. That will soak up the water as it comes off the coils. It's just a fix for now.