Start with a flow that has a Send an email action.

  1. Select Show advanced options, which is located at the bottom of the Send an email card.

    You'll then see the advanced options for sending an email.

    Sharepoint triggers

  2. Select High from the Importance list, and then select Hide advanced options to hide the advanced options.

  3. Select Update flow, which is located on the menu at the top of the screen.

    This step saves your changes.

Source: Microsoft