To recruit means to get someone to join something. You might recruit people for the navy or you might recruit members for your quilting group.
The verb recruit often refers to formally joining an organization or a group, such as the military or a corporation. It can also be used more broadly to refer to getting someone to participate in a cause, formal or otherwise, like when you recruit your friend to help paint your room. As a noun, recruit means "a person who has been recruited." If you just joined the Army, you're a new recruit.