/Shout is area-wide. If you're in Central Shroud and you /Shout, everyone in Central Shroud hears you. I'm not sure exactly what /Yell does, but I think it's slightly smaller scale. /Say is a small local area chat. In parties, people use /Party. Amazingly, this game has very little spamming. People mostly only use /Shout to call hunt marks and other things. Only the major end-game hub towns have some degree of /Shout spam. There is no server-wide chat, which is nice since it would be a bot's paradise and we have no need of it with the Market Board and Party Finder anyways.

For some raiding parties, people will use Discord or some other voice chat program.

For the Novice Network, I believe you have to be invited by a Mentor (a player with a Crown icon next to their name).