Rent Auto Payment instead of using drop box

[Abdessettar Ibourki]

Just got my first 4 unit with tenants still in lease. They currently drop the rent checks in a drop box.

1. Any idea of how to switch this to an automatic payment instead, even though it is not mentioned in the leases.
2. Any Suggestion of the best services/websites (as a 3rd party) that provide this auto payment 

Thanks.