A matter to be dealt with; business or the reason for contacting someone—often the point or agenda of a call or meeting.
電話の用件を手短に話してください。
Please state the purpose of your call briefly.
会長に伝える用件が三つあります。
I have three matters to report to the president.
用件が済んだら戻ってきてください。
Please come back after you've taken care of your business.