PHPMailer

<?php

// Definir ruta principal
define('HOMEDIR',__DIR__);

use PHPMailer\PHPMailer\PHPMailer;
use PHPMailer\PHPMailer\Exception;

require HOMEDIR.'/PHPMailer/Exception.php';
require HOMEDIR.'/PHPMailer/PHPMailer.php';
require HOMEDIR.'/PHPMailer/SMTP.php';

$mail = new PHPMailer(true);
try {
    //Server settings
    $mail->SMTPDebug = 2;                                 // Enable verbose debug output
    $mail->isSMTP();                                      // Set mailer to use SMTP
    $mail->Host = 'mail.*******.com';  // Specify main and backup SMTP servers
    $mail->SMTPAuth = true;                               // Enable SMTP authentication
    $mail->Username = 'account@*******.com';                 // SMTP username
    $mail->Password = '***********';                           // SMTP password
    $mail->SMTPSecure = 'tls';                            // Enable TLS encryption, `ssl` also accepted
    $mail->Port = 465;                                    // TCP port to connect to

    //Recipients
    $mail->setFrom('account@********.com', 'Cuentas');
    $mail->addAddress('********@gmail.com');     // Add a recipient
    //$mail->addAddress('ellen@example.com');               // Name is optional
    $mail->addReplyTo('account@tuberfly.com', 'TuberFly Cuentas');
    //$mail->addCC('cc@example.com');
    //$mail->addBCC('bcc@example.com');

    //Attachments
    //$mail->addAttachment('/var/tmp/file.tar.gz');         // Add attachments
    //$mail->addAttachment('/tmp/image.jpg', 'new.jpg');    // Optional name

    //Content
    $mail->isHTML(true);                                  // Set email format to HTML
    $mail->Subject = 'Bienvenido';
    $mail->Body    = 'Te has registrado <b>correctamente</b> en ***** y ahora ya puedes comenzar a usar nuestros servicios.';
    $mail->AltBody = 'Te has registrado correctamente en ********* y ahora ya puedes comenzar a usar nuestros servicios.';

    $mail->send();
    echo 'El mensaje ha sido enviado correctamente';
} catch (Exception $e) {
    echo 'Message could not be sent. Mailer Error: ', $mail->ErrorInfo;
}