Choose the Pets OK amenity when you set up the unit. This will show up on your Caretaker and Apartment App listings, and on partner websites. For example, if you selected Pets OK then your listing will show up on Apartments.com as Dog Friendly and Cat Friendly.
If you do not allow pets, simply leave this checkbox unchecked. On all platforms, if your listing does not have a marker that says pets are accepted it means that they aren't. When someone filters their search to make sure they see listings that allow pets they won't see yours.