If you want to use gmail smtp server to compose emails to send your emails, use the below code snippet to configure your PHPMailer. Each emails you send will be available in your GMail's sent folder.

phpmailer-gmail-configuration.php

<?php
$mail = new PHPMailer();

$mail->isSMTP();
$mail->SMTPDebug = 2;
$mail->SMTPAuth = true;
$mail->Host = 'smtp.gmail.com';

$mail->SMTPSecure = 'tls';
$mail->Port = 587;
// tls on 587: strong, recommended
// ssl on 465: weak, old

// https://en.wikipedia.org/wiki/SMTPS - Deprecated
// https://myaccount.google.com/permissions
// https://myaccount.google.com/lesssecureapps
// Enable less secure password

# Your gmail login details
$mail->Username = '[email protected]';
$mail->Password = 'gmail-password';

$mail->setFrom("", "First Last");
$mail->addReplyTo("", "First Last");
$mail->addAddress("", "John Doe");
$mail->Subject = "PHPMailer GMail SMTP test";
$mail->msgHTML(file_get_contents("test/contents.html"), __DIR__);
$mail->AltBody = "This is a plain-text message body";
#$mail->addAttachment("images/logo.png");

if (!$mail->send()) {
    echo "Mailer Error: " . $mail->ErrorInfo;
} else {
    echo "Message sent!";
}