You´ll need papers for the boat and sometimes licenses to operate and buy a VHF and short wave radios. To obtain those certificates you might be required to attend a few marine classes. They take around a week or so, do them well in time. Check with your boat dealer or a Marina.
The papers for the boat will work as a "passport" for the vessel and should include an proof of ownership with the boats name on, a description of data's such as tonnage, height and other. For launches, it is also good to have a snapshot of the hull and keel.
Be sure to obtain the visas required depending on your route. You´ll be checking in and out of foreign ports and they will need clear papers, your passport and sometimes a declaration of your valuables for customs. A crew list with passport numbers could also be required. Usually, the procedure is quick and simple, providing you have your papers in order.
Luckily, cruising the world is still a pretty uncomplicated procedure. Paperwork will be pretty simple, your headaches will rather come from reading manuals, and replacing failing parts at Tonga.