There are a few things you need to do in order to adopt a pet in Sims 4 on PS4. First, you will need to create a Sim account and select the “Pet” tab. Next, you will need to fill out the adoption form and provide your Sim’s name, age, gender, and other information. Finally, you will need to pay for the adoption fee and receive an adoption key. Once you have received your adoption key, you can enter it into the pet’s room in your home and begin adopting them!