There are five required text fields for a single mission, six if it's possible for the mission to be failed. Let's go over each one below.
Mission Introduction Dialog
The first dialog the players read regarding the mission. It's spoken by the Story Contact to the players.
Example: I really need your help with something. There's this guy... and, uh, he's doing something really bad.
Mission Send Off Dialog
The dialog the players read after they accept the mission from the Story Contact.
Example: Thank you so much for helping me. This guy hangs out in this old office building. His name's Frostfire; he's a member of the Outcasts.
Compass Active Task Text
This is a short description displayed in the navigation or compass window while the players are on the mission.
Example: Defeat Frostfire
Still Busy Dialog
The dialog given by the Story Contact if the players returns to them but haven't yet completed the mission.
Example: Have you taken out Frostfire yet? It's really important for you to go into that old office building and have a talk with him, preferably with your fists.
Return Success Dialog
This is the dialog given by the Story Contact when the players return after successfully completing the mission.
Example: You did it! I can't believe you took out Frostfire. Did he happen to mention anything about my sister? That's why I wanted you to talk to him. Did I forget to mention that?