@Cindy1044
1) You may require in your House Rules that guests tell you about any animals they plan to bring when they're booking. Be aware that Airbnb's Assistance Animal policy tells guests that they're not required to disclose their pets if they consider them to be "emotional support animals," so there's nothing specifically stopping someone from arriving with a Comfort Crocodile and nailing you for discrimination if you turn them away.
2) Pet fees can't be added to the booking payment process, but if it's disclosed in your listing, you can request that guests accept a Resolution Request before check-in before their pets can be admitted. Once again, Airbnb lets guests get around that if they claim to have an assistance animal.
Also note that the Host Guarantee does not offer coverage for damage caused by pets (although in practice, it doesn't cover much else either) and there is no actual security deposit. Some hosts have changed their minds about pets upon learning this.