The Dropbox desktop app includes a Dropbox icon in your taskbar (Windows) menu bar (macOS), or system tray (Linux).
The Dropbox icon in your taskbar or menu bar is a shortcut to jump back into your work, right from your desktop, and it gives you quick access to most key features of Dropbox and information on your sync and storage status.
If your files are fully synced, this will look like a solid black Dropbox icon with no other icons. If you have unread notifications, this icon will feature a red circle with a white number in it. Learn more about sync icons in the Dropbox desktop app for Windows and Linux or macOS.