Do you mean you want to become a host but don't actually have a property to list ? @Elder-LeRoy0 ?
1. check out if there are any STR restrictions in the area you want to host in.
2. You need permission from a landlord if you want to sublet their property many have clauses in their lease forbidding it
3. read the Airbnb Help FAQs to familiarise yourself with how Airbnb works