PHPMailer dynamic mail recipient insertion - php

Question

We all know how to implement PHPMailer within a project and its use is great, but I need something more, after entering the necessary parameters in order to make everything work.
I need a form to change the email address of the recipient who will receive the email, how can I do?
code:
<?php
use PHPMailer\PHPMailer\PHPMailer;
use PHPMailer\PHPMailer\Exception;
require 'PHPMailer/src/Exception.php';
require 'PHPMailer/src/PHPMailer.php';
require 'PHPMailer/src/SMTP.php';
$mail = new PHPMailer(true); // Passing `true` enables exceptions
try {
//Server settings
$mail->SMTPDebug = 0; // Enable verbose debug output
$mail->isSMTP(); //Set mailer to use SMTP
$mail->Host = 'smtp.gmail.com'; // Specify main and backup SMTP servers
$mail->SMTPAuth = true; // Enable SMTP authentication
$mail->Username = 'xxx#gmail.com'; // SMTP username
$mail->Password = 'xxx'; // SMTP password
$mail->SMTPSecure = 'tls'; // Enable TLS encryption, `ssl` also accepted
$mail->Port = 587; // TCP port to connect to
//Recipients
$mail->setFrom('xxx', 'xxx'); // Sender email and name
$mail->addAddress('xxx'); // Reciver email
// if you want to send email to multiple users, then add the email addresses you which you want to send.
//$mail->addAddress('reciver2#gmail.com');
//$mail->addAddress('reciver3#gmail.com');
//For Attachments
//$mail->addAttachment('/var/tmp/file.tar.gz'); // Add attachments
//$mail->addAttachment('/tmp/image.jpg', 'new.jpg'); // You can specify the file name
//Content
$mail->isHTML(true);// Set email format to HTML
$mail->Subject = 'Oggetto dell email'; // Subject of the email
$mail->Body = 'This is the HTML message body <b>in bold!</b>';
$mail->send();
echo 'Message has been sent';
} catch (Exception $e) {
echo 'Message could not be sent. Mailer Error: ', $mail->ErrorInfo;
}
?>