Townspeople can go to the Adventurer's Guild and submit a wide variety of requests. The guild accepts requests such as killing a monster, mediation, escorting, delivery, asking for donations for a certain cause, retrieving lost items, etc. The cost of the requests depends on the type of the request. Mediation requests are low in price.
Almost anybody can be recruited into the Guild. The most basic qualification is to have a certain level of fighting ability, weapon or magic. However, people who have the appearance of being underaged could be rejected without a recommendation by another adventurer.
The Certification Exam is a required test that is given to new applicants. The main purpose of the exam is to measure the applicants abilities as adventurers. There is no official format for the exam, but those who take it are usually given 3 requests made by the citizens and have rewards for their completion.