Hanako Side Quest - Persona 2: Innocent Sin Guides
The Hanako Side Quest is the first in the game that you will come across. At the start of this quest you will get a bit of details about rumors, how they work and how to spread them. Since this is the first side quest of the game that involves rumors giving you a bit more details on how the whole system works is needed.
In order to start this quest you'll first need to speak with a student at the Seven Sister's High inside of Class 2-B. He'll tell you about a monster named Hanako that he saw and he asks you to return proof that this monster exists. The first thing you'll need to do after learning this rumor is to head over to the Kuzunoha Detective Agency which is where you'll be able to spread this rumor.
Once the rumor is spread you'll be able to encounter Hanako as a random encounter inside of the Seven Sister's High. When you defeat Hanako you'll be rewarded with Hanako's Nametag which you'll want to return to the same student who started this quest for a reward.