To change this setting, head to Settings > All Settings > Preferences > Notifications on your Xbox One.

You could disable the “Notifications on” checkbox here and prevent your Xbox One from showing you notifications at any point.

Select “Xbox notifications”.

You’ll see a list of different categories of notifications, including categories like Friends & broadcasts, Achievements, Messages, Incoming calls, and System. These categories all have separate settings.

To prevent a type of notification from appearing while you’re watching videos, select it here. If you want to prevent all notifications from appearing while you’re watching videos, just select the first category—you’ll have to change this setting separately for each category of notifications.

Enable the “Hide pop-ups during video” checkbox for the notification. Press the B button on your keyboard to go back and repeat this process for each type of notification you want to hide while watching videos.