If you want to send a mail to wordpress admin when user comes to 404 page. Then you can write the below simple code in theme’s functions.php file or you can write the same in custom plugin created by you.
Magento & WordPress Web Developer in India
If you want to send a mail to wordpress admin when user comes to 404 page. Then you can write the below simple code in theme’s functions.php file or you can write the same in custom plugin created by you.