Even though your are most likely on Instant Book on Airbnb, you can still receive request to book reservations in certain cases. These cases include:
The reservation dates are shorter than the advance notice requirements for the listing and you allow Request to Book for shorter notice reservations.
Guest does not meet the requirements set by you for booking instantly.
There are specific restrictions on the listing or guest party, e.g. the listing is not suitable for children but the guest's party includes children.
In any case, Uplisting supports request to book reservations on Airbnb. You can accept, deny and send messages on each request.