Quests: Area tasks
In some zones you can receive individual quests if you pay close attention to what is happening around you. Sometimes a hero is explicitly asked for help, and sometimes you have to figure things out on your own.
You can view or cancel your current quests with the quests command. The reward for such quests is usually experience, gold, and various useful items. Some quests can be completed once per reincarnation, while others can be completed once a day, but no more than 10 times.
If something goes wrong, the quest can be cancelled and started again the next day.
The help article for each zone lists the quests available there. Here are a few examples to get you started: