Federal vs state
Federal: OUPV from USCG (everything on this site). State: a separate fishing-guide license issued by the state's fish and wildlife department, typically required if you take any compensation as a fishing guide. The state license usually requires only an application + fee + sometimes a state-water knowledge exam — much lighter than the federal OUPV.
Bluewater and canyon trips
If your charter goes more than ~3 nm offshore, OUPV Near-Coastal is the right credential — it extends authority out to 100 nm and tests you on COLREGs (International Rules), which is what's enforced offshore.