Spaceman is an application for macOS that allows you to view your Spaces / Virtual Desktops in the menu bar. Spaceman allows you to see which space you are currently on (or spaces if you are using multiple displays) relative to the other spaces you have. Naming these spaces is also an option in order to organise separate spaces for your workflow.
The style and the name of a space can be changed in preferences (shown above). A space is named by selecting the space from the dropdown, typing a name up to 3 characters and clicking the 'Update name' button or pressing enter.
If the icon fails to update, you can choose to force a refresh of the icon using a custom keyboard shortcut or allow Spaceman to refresh them automatically every 5 seconds by enabling 'Refresh spaces in background'. See #2.