Make certain you click on the correct category (i'll assume you are going rec)
Once you click on the category (general, harpoon, recreational, ect...)
They don't allow you to go back & change in the same year.
I think you have 10 days to make a change. But best to get it right the first time.
Something to consider if you are aren't dead set on being commercial is that with a gen cat permit, all you can fish for is tuna. You can't target sharks, swordfish or billfish unless you have separate permits for them (and those are all hard to get).
With an angling permit, you can't sell your catch, but you can land sharks, swordfish, and billfish.
Charter/headboat allows you to live in both worlds (but not on the same day). You can sell tuna, but you can also fish under rec rules. You do however need an mmc (oupv or masters) on board.