$m = new PHPMailer;

$m->isSMTP();
$m->SMTPAuth = true;

$m->Host = "smtp.gmail.com";
$m->Username = "mymail@gmail.com";
$m->Password = "mypass";
$m->SMTPSecure = "ssl";
$m->Port = "465";

$m->isHTML();

$m->Subject = "Hello world";
$m->Body = "Some content";

$m->FromName = "Contact";

$m->addAddress('mymail@gmail.com', 'Test');

Solution:

$mail->From = 'user@domain.com';

$m->isHTML(true);

$mail = new PHPMailer;
$mail->isSMTP();/*Set mailer to use SMTP*/
$mail->Host = 'mail.domain.com';/*Specify main and backup SMTP servers*/
$mail->Port = 587;
$mail->SMTPAuth = true;/*Enable SMTP authentication*/
$mail->Username = $username;/*SMTP username*/
$mail->Password = $password;/*SMTP password*/
/*$mail->SMTPSecure = 'tls';*//*Enable encryption, 'ssl' also accepted*/
$mail->From = 'user@domain.com';
$mail->FromName = $name;
$mail->addAddress($to, 'Recipients Name');/*Add a recipient*/
$mail->addReplyTo($email, $name);
/*$mail->addCC('cc@example.com');*/
/*$mail->addBCC('bcc@example.com');*/
$mail->WordWrap = 70;/*DEFAULT = Set word wrap to 50 characters*/
$mail->addAttachment('../tmp/' . $varfile, $varfile);/*Add attachments*/
/*$mail->addAttachment('/tmp/image.jpg', 'new.jpg');*/
/*$mail->addAttachment('/tmp/image.jpg', 'new.jpg');*/
$mail->isHTML(false);/*Set email format to HTML (default = true)*/
$mail->Subject = $subject;
$mail->Body    = $message;
$mail->AltBody = $message;
if(!$mail->send()) {
    echo 'Message could not be sent.';
    echo 'Mailer Error: ' . $mail->ErrorInfo;
} else {
    header("Location: ../docs/confirmSubmit.html");
}

SMTP Error: Could not connect to SMTP host. Mailer Error: SMTP Error: Could not connect to SMTP host.

include("phpmailer/class.phpmailer.php");
$mail = new PHPMailer();
$mail->IsSMTP();
$mail->SMTPAuth = true; // enable SMTP authentication
$mail->SMTPSecure = "ssl"; // use ssl
$mail->Host = "smtp.gmail.com"; // GMAIL's SMTP server
$mail->Port = 465; // SMTP port used by GMAIL server

Solution:

 $mail = new PHPMailer();
 $mail->IsSMTP(); // send via SMTP
 $mail->Host = SMTP_HOST; // SMTP servers
 $mail->Port = SMTP_PORT; // SMTP servers
 $mail->SMTPAuth = true; // turn on SMTP authentication
 $mail->Username = SMTP_USER; // SMTP username
 $mail->Password = SMTP_PASSWORD; // SMTP password
 $mail->From = MAIL_SYSTEM;
 $mail->FromName = MAIL_SYSTEM_NAME;
 $mail->AddAddress($aSecuredGetRequest['email']);
 $mail->IsHTML(true); // send as HTML

Solution

    SMTP Error: Could not authenticate. Error: SMTP Error: Could not authenticate.

    SMTP server error: 5.7.1 Username and Password not accepted. Learn more at 535 5.7.1http://mail.google.com/support/bin/answer.py?answer=14257 p38sm2467302ybk.16

 <?php
  require_once ("PHPMailer\class.phpmailer.php");
  $Correo = new PHPMailer();
  $Correo->IsSMTP();
  $Correo->SMTPAuth = true;
  $Correo->SMTPSecure = "tls";
  $Correo->Host = "smtp.gmail.com";
  $Correo->Port = 587;
  $Correo->UserName = "foo@gmail.com";
  $Correo->Password = "gmailpassword";
  $Correo->SetFrom('foo@gmail.com','De Yo');
  $Correo->FromName = "From";
  $Correo->AddAddress("bar@hotmail.com");
  $Correo->Subject = "Prueba con PHPMailer";
  $Correo->Body = "<H3>Bienvenido! Esto Funciona!</H3>";
  $Correo->IsHTML (true);
  if (!$Correo->Send())
  {
    echo "Error: $Correo->ErrorInfo";
  }
  else
  {
    echo "Message Sent!";
  }
?>