<?php

add_filter( 'wp_mail_from', 'mycustom_wp_mail_from' );
function mycustom_wp_mail_from( $from_email ) {
	return 'abc@xyz.com';
}

add_filter( 'wp_mail_from_name', 'mycustom_wp_mail_from_name' );
function mycustom_wp_mail_from_name( $from_name ) {
	return 'John Doe';
}

?>