The Focused event fires when the /TextBox gains focus - typically when a client clicks/taps on a TextBox to begin text entry. This also fires if a TextBox forces focus on the user.
It can be used alongside TextBox.FocusLost to track when a TextBox gains and loses focus.
This example works when placed in a /LocalScript that is the child of a TextBox. When the TextBox gains focus, the example prints “Focus”.