The BOC-3 is the form used by the FMCSA to list the "process agents" in all states. A "process agent" acts as a representative to forward legal or court documents in any proceeding that might be brought against your company. Having a process agent listed in all 50 states is known as; a "blanket coverage". Everyone who files for MC Interstate Authority is required to have a BOC-3 on filed with FMCSA.
To transport goods for hire (drive across state lines with property that is not your own or with passengers), you are required by law to have an FMCA Operating Authority. Anyone can now get their own authority rather quickly (usually in 30 days or less) and at a reasonable cost.
Intra authority is required to pick up and deliver goods inside the same state.
Because these authorities are issued by each state individually, the costs and requirements vary. In general you must have primary liability and cargo insurance filed as a Form E (liability) and Form H (cargo) at the State.
An application and fees must be filed and with some exceptions, authorities are issued in 2-8 weeks.