In the Marvin desktop app, you can see the task you are tracking time on in your system tray. On a Mac, that's the menu bar at the top of the screen. On Windows, it's the area next to the clock.
This is only in the desktop app. The web app and the phone apps don't have it.
What shows there
While you track time on a task, a timer icon appears in the tray. On a Mac, the task's title is shown next to the icon. On Windows, hover over the icon to see it. The icon goes away when you stop tracking.
Screenshot to add: The tracked task in the Mac menu bar
What you can do from it
Click the icon to open its menu:
Stop/pause tracking
Mark Done: completes the task you are tracking
Open Amazing Marvin: brings the Marvin window to the front
Turn it on
Open the Features page and find Time Tracking.
Open its settings.
Turn on System tray indicator.
The setting only shows up in the desktop app.
Other desktop extras
App Badge: a small red number on Marvin's app icon showing how many open tasks are in your day or in a smart list. Turn it on in Settings.
Add Task from the Dock (Mac): right-click the Marvin icon in your Dock and choose Add Task.
Top of Mind: a small floating window that shows your current task on top of your other apps.
See The Marvin desktop app for more about the desktop app.