What is a Team Officer?
Officers are special members of the team who can remove and accept team applicants. In addition, officers can also declare war on other teams. Officers cannot change the team's details (coat of arms, description, etc.) and cannot kick other officers out.
How do I become a Team Officer?
The leader of the team has the ability to promote and demote team members from Officer status. The button to do this is on the person's profile (you should see a Demote or Promote button).