If you see any mission you wish to partake in on the Mission List, and your rank allows you to perform in that mission, you may request it here, assuming no one else is performing in it. Exceptions are given if your character has permission to perform in a ranked mission higher than what your character's rank is. If missions require a certain amount of people to do them, make sure to find the appropriate number to carry out the mission with you. For example, some missions require the normal three-man cell make up, and some require that with a Chuunin or Jounin as the leader.

Even if a mission just needs one person, if you want to do the mission with others to help, then you may do so. It will help you all in performing teamwork while still making the mission easier. Do know, however, that the rewards will have to be split between you all, unless your teammates are generous enough to let you get away with most of it.