Right click on the timecode (not shown in your screenshot) to the left and top of your sequence and choose one of the options.
Change how timecode is displayed
You can change the timecode display format in any panel where timecode is shown in hot text.
(Optional) To display timecode in audio units (Audio Samples or Milliseconds), click the panel menu button
in the panel desired, and select Show Audio Time Units.
Ctrl-click (Windows) or Command-click (Mac OS) a hot text timecode display to toggle through any of these timecode formats that are available. The last two are available only if you select Show Audio Time Units in the panel menu.