Here's how to get rid of that "Get Windows 10" tray icon:
1) Open Windows Update by going to Control Panel -> System and Security -> Windows Update, or search for it.
2) Click on Installed Updates on the bottom left corner.
3) Locate and select the Update for Microsoft Windows (KB3035583) update under Microsoft Windows section. You can search for KB3035583 in the search box on top left corner.
4) Click on Uninstall to remove the update.
5) Click Yes to confirm.
6) When uninstallation process is completed, restart the computer.
You're now free from Get Windows 10 system tray icon and Windows 10 free upgrade offer reservation nag screen.
Source:
https://techjourney.net/disable-rem...de-reservation-notification-system-tray-icon/