Notifications are turned on for any messages in your Primary label by default.
1. On your iPhone, open the Mobile App.
2. Tap the SideMenu icon at the left of your navigation bar to open the Side Menu.
3. Tap the Gear icon at the bottom of the Side Menu to bring up Settings.
4. Tap Mail.
5. Select your account.
6. Tap Notifications.
7. Turn the Allow Notifications radio button on/off.