***If you have an animal emergency, please get in touch with your local veterinarian.
The best way to get a cat back home to its owner is often just to leave it where it is. This way the owner can find it; the cat likely belongs to one of your neighbors. If the animal has an ear tip (an ear with its tip cut off diagonally), this may indicate that the cat is feral but has been previously trapped and spayed or neutered. At some point, it was determined that this cat was not suitable for adoption. You should not try to pick it up or handle it as it is most likely more wild than tame. (NOTE: Occasionally, tame cats do end up with ear tips.)
If you are concerned about a tame/stray cat, you can take the cat to your nearest veterinary clinic or animal shelter to have the animal scanned for a microchip. If it has a microchip, the veterinarian or shelter will help contact the owner or give you information to contact the microchip company to find the owner.