Once you have successfully installed the extension, go to Stores → Configuration to configure the extension for use. Here you can find various settings for the extension.
- 404 Notifier: Enable or disable 404 Notifier extension from here.
- Send Emails To: Enter Email ID of the admin on which you want to receive mails for 404 page notifications.
- Email Sender: Select Email sender from the drop down.
- Email Template: Select template for 404 notification Email.