[header] How to take in a stray cat [title] Make sure the cat you've found is a stray for sure. [step] Take the cat to a vet and ask them if there is a microchip in the cat. The vet will be able to tell if someone owns the cat if a microchip exists. 
The vet may also have notices of any missing cats you can check. [substeps] If the microchip doesn't exist or the owner cannot be traced this way: leave a message on online sites that help people find lost cats.