Cats scratch wood and upholstery to exercise and to sharpen their claws. If your cat doesn’t have access to trees, provide a scratching post to prevent furniture damage.
The post should be stable and tall enough for the cat to stretch out. It can be a bark-covered log or a 2 x 2 nailed to a base of 1/2-inch plywood and covered with burlap or a piece of wool carpet. Attract your cat to the post by rubbing catnip on the post or by attaching a toy on a string to the top of the post.
If the cat still claws, apply a cat repellent to the furniture or squirt the cat with water from a squirt gun when it claws. When training a kitten, restrict it to the scratching post area until it learns to use the post.