Sent WordPress emails with SMTP - Deliver emails reliably by using SMTP. Use a tiny streamlined plugin to keep things fast. https://www.damiencarbery.com/2019/01/send-wordpress-emails-with-smtp/

send-emails-via-smtp.php

<?php
/*
Plugin Name: Send email via SMTP
Plugin URI: https://www.damiencarbery.com/2019/01/send-wordpress-emails-with-smtp/
Description: Send emails via SMTP.
Author: Damien Carbery
Version: 0.1

*/

add_action( 'phpmailer_init', 'send_smtp_email' );
function send_smtp_email( $phpmailer ) {
	$phpmailer->isSMTP();
	$phpmailer->Host       = 'smtp.yourhost.com';
	$phpmailer->SMTPAuth   = true;
	$phpmailer->Port       = 587;
	$phpmailer->Username   = 'me@mydomain.com';
	$phpmailer->Password   = 'ThisIsNotMyPassword';
	$phpmailer->SMTPSecure = 'tls';
	$phpmailer->From       = 'me@mydomain.com';
	$phpmailer->FromName   = 'My Name';
}