Definitions of swear in
to make someone take an oath (=a promise that a person will tell the truth) as a witness (=someone who tells a court what they know about something that has happened) in a court
I'd like to swear the witnesses in at this time. Please raise your right hand.
to make someone take an oath (=a promise to act a certain way in the future) to act in an official capacity
He was sworn in as King Felipe VI on Thursday.