@Brian3122 , as @Mike-And-Jane0 , has stated Airbnb does not in any manner assist with creating a tenancy and/ or assist in an eviction process. As the homeowner, this is on you, but as @Mike-And-Jane0 , asked why would you, especially in the state of California, in which tenants have more protections than landlords. Any stays longer than 30 days in the state of California, your guest has now turned into a tenant and has all the rights under the state of California renter/landlord laws provides.
Do your research and protect yourself from costly errors…