Litter box issues is one of the most common reasons cats are surrendered to shelters. However, litter box use is INSTINCTUAL for cats. When cats don't use their litter box, it's usually for three common reasons: illness, stress, or dislike of the litter box.
The first step whenever any cat has litter box issues is to immediately get them to a veterinarian. The veterinarian will take a history, run a urinalysis, and determine if there are any conditions that may be causing the cat to have pain while using the litter box. If you cannot afford a visit to a veterinarian, see the "Medical Issues" section for available resources.
Litter box issues is also one of the most common side effects of declawing. If your cat is declawed, your veterinarian can perform x-rays to look for signs of remaining bone fragments in the paws, as well as signs of early onset arthritis. The pet may need medication to control their pain while using the litter box, as well as a change in litter that is more comfortable for their paws. If you cannot afford a visit to a veterinarian, see the "Medical Issues" section for available resources.
If a veterinarian has determined the cat does not have a urinary tract infection and the cat is not declawed, there is likely a behavioral or environmental element that needs to be addressed. See the "Behavior Issues" section for available resources.