This is called clotting. Clotting slows down bleeding. Press on the cut to help slow down the bleeding. You may have to apply pressure for 10 minutes or more for a bad cut. Sometimes a cut needs stitches.
Stitches help the cut heal.
The cut is longer than an inch and located on an area of the body that bends, such as the elbow, knee or finger. The skin on the edges of the cut hangs open. Bleeding from what seems to be a minor cut continues after 20 minutes of applied pressure. Put on disposable latex rubber gloves, if available. Put pressure on the wound for at least 10 minutes.