Check out this article to see how to set or change your pet fee on Airbnb. Once your pet fee is added, it is included in your guest's reservation when they add a pet.
Pet fees are not shown to guests as separate line items, the pet fee is added to the guest's nightly price.
A good way to see your pet fee on Airbnb is by checking the prices with & without a pet included, see below:
Note that the dates are the same, however, when the pet is included the nightly rate shows as €115 per night (€30 pet fee, over 2 nights it equals €15 per night - if the reservation was for 3 nights it would show €110, etc)