How do I change the default email notification settings for a specific user in SharePoint?

Determine Email Notification Rules
Before changing the email notification settings for a specific user, review the SharePoint site permissions to ensure that the user has adequate access to the element that will be subject to the Notification setting changes.
Log in to the SharePoint Site
Log into your SharePoint site with a user that has suitable permissions to view user settings and manage them.
Navigate to the User Record
Locate the user record in the SharePoint site for the underscore user whose settings need to be changed.
Access the User’s Settings
Once you have located the user’s record, access the settings.
Modify the Default Email Notifications
Now you can adjust the settings to modify the user’s email notification preferences.
Save Changes
Once you have updated the user’s email notification settings, save any changes that you have made.