After Monosnap launch, you can see a small square with the Monosnap logo in the Desktop's right bottom corner. It's Dropzone.
Dropzone allows to:
1️⃣ Open Monosnap's main menu by click on it.
2️⃣ Upload file to cloud storage or open a file with drag & drop.
If you prefer using hotkeys or Monosnap's icon in the tray. You can hide or show Dropzone with a default hotkey Ctrl+Alt+F or an option on the main menu.
In the Settings > Hotkeys, you can set up a custom hotkey to hide or show Dropzone.