What is the difference between a cat spraying and a cat urinating?

Cats urinate through the same mechanisms as most land mammals. They store up urine in the urinary bladder, then when the urinary bladder is full they look for a safe place to urinate at. Typically cats prefer to bury their urine, so they will often look for soft dirt, sand or other absorbent/draining surfaces to urinate on. They posture then relax the sphincters around the urethra to allow urine to flow out, often accompanied by contractions of the urinary bladder to fully empty it out. Once done, the cat will often circle around, sniff the area to see how strong the odor is, then scratch the surrounding surface with their front paws to cover the urine and mask the scent. One exception to this is an intact male cat who is marking his territory - he will often spray urine around at tail height deliberately as a way of warning off rivals.