Are you looking for a way to change the "from email address" in your WordPress theme? 

All you have to do is add this code to your WordPress active theme’s functions.php file:

add_filter('wp_mail_from', function ($email){
   return 'no-reply@blogname.com';
});

Don't forget to change the red-marked code (set the right email) before using it. 

This is a small instruction on How to Easily Add Custom Code in WordPress:  https://www.wpbeginner.com/plugins/how-to-easily-add-custom-code-in-wordpress-without-breaking-your-site/

More info for the wp_mail_from hook here: https://developer.wordpress.org/reference/hooks/wp_mail_from/