To do ANYTHING, you must send a form. You can find every form on the Forms Page. A form is simply used as way for us to update, and keep track of, your character's activities. While Role-Playing on the Message Board is optional, sending in forms is not.
The vast majority of forms are NOT allowed to be sent on major holidays, or any other day so stated by an updater. These days are considered non-operating days. However, certain forms ARE allowed on non-operating days, though they will not be updated until normal operating days. These forms are Create A Team, Official Challenges, QCCS Page, Reminder, Universal Market, and Join Forms.