On the My flows tab of the Flow app:

  1. Select the flow you wish to manage:
    Overview image
  2. You can tap any of these options, based on what you'd like to accomplish:
    Overview image
  3. Tap Delete flow to delete a flow.

Note All run history is deleted when you delete a flow:
Overview image

  1. Tap Update after you are done editing a button flow, to save your changes:
    Overview image
  2. Tap Run history to see the results of all runs of a particular button flow:
    Overview image
  3. If you disable a flow, it will no longer be available on the Buttons tab:
    Overview image
Source: Microsoft