How to turn off all notification window 10

1. Select Start in the bottom left-hand corner of your desktop.

2. Choose Settings (looks like a gear).

3. Select System.

4. From the sidebar, select Notifications & actions.

5. Under Notifications, toggle off Get notifications from apps and other senders.

Ref: https://www.lifewire.com/turn-off-notifications-in-windows-10-5189206