Hello @Matoska-Ridge0,
That setting is in the "House rules" section.
One way to get to it is as follows.
On your computer go to your calendar and click on "Manage settings" in the top right hand corner.
Then click on "Booking settings" and scroll down to the "House rules" section.
Now click on the "Edit" button for that section and click to turn off "Pets allowed".
Then select "Save".
On the Android app tap on "Listings" and then select your listing.
Then tap "Booking settings" followed by "House rules". Then tap to turn off "Suitable for pets".
Now tap "Save".
I don't have an Apple device so don't know what the procedure is for them.
Steve.