The natural scratching behavior of cats
All felines occasionally need to sharpen their claws. And although you may not be particularly fond of this activity, know that it’s a completely natural and instinctual behavior that serves a variety of purposes for your cat. Not only does it help strip away the worn outer claw for a healthier one underneath, but it is also an inherent way for your cat to mark territory with secretions from scent glands.
And finally scratching is a way for your cat to strengthen and stretch his/her back and leg muscles. (Never declaw your cat, it is an extremely painful, unnecessary and cruel process. There are many declawed cats at nearby shelters who need a good home.)
There are ways to deter this activity to a more appropriate place such as a scratching post.
Provide special toys and treats and lots of attention by the scratching post to associate a positive environment. Keep your cat mentally stimulated and offer plenty of opportunity for play and exercise. Cover certain areas or corners of your furniture while training with plastic, aluminum foil or double-sided sticky tape. (Always make sure to supervise so that it doesn’t harm your cat!) Spray a citrus scent to the area to deter. Keep nails trimmed regularly. Also, consider a window perch to provide hours of distraction and entertainment for your cat.