Depends whether it is a vinyl, vinyl coated, foil or paper wall paper. If you are going to paint the wall, if the seams are solid, you can paint the wallpaper with a oil based primer then use latex. Saves a lot of work.
I shared this tip with another post: score the wallpaper then use a mixture of equal parts of liquid fabric softener (downy or generic) with water. Roll this on with a paint roller or wash it on with a rag. Wait a few and you should be able to peel off the wallpaper. The fabric softener loosens the glue so you can remove it. This is the only thing that worked for my awful project of removing wallpaper from every wall in my current house! (and I tried everything).
Go really slow and do a test in a very small area. Sadly, I removed wallpaper once from drywall that the previous owner hadn't primed! IT PEELED OFF THE PAPER COVERING ON THE DRYWALL.
Use warm water with a sponge, over and over. This will losen the paper and glue so that you can scrape it off with a flexible putty knife. If the paper has a shiny finish, scuff it up with sandpaper before wetting.
Best, Charles