Quests are objectives for players to complete that reward XP. They are a large portion of the experience needed to level up from 16-20. A zone's quest will not appear until your character reaches a specific level, which is different for each zone.
Each zone has a separate quest, and a new random quest is automatically given when the previous one is turned in. The following zones have quests: Fjolarok, Fjolgard, Fjolgard Sewers, Crystal Caves, Temple, and the Pyramid of the Sun.