bootstrap mail form $from<$email> $fromEmail - mail-form

Question

I refer to this page. https://bootstrapious.com/p/how-to-build-a-working-bootstrap-contact-form and i uesd index-2.html / contact-2.php files.
i want mailheader ''
but code is
**$fromEmail = 'demo#domain.com';
$fromName = 'Demo contact form';**
$sendToEmail = 'my#mail.com';
$fields = array('name' => 'Name', 'phone' => 'Phone', 'email' => 'Email', "\r\n" , 'message' => 'Message');
so i changed
$fromEmail = "$email" $fromName = '$name'; or
$fromEmail = $_POST['form_email']; $name = $_POST['name'];
but It just makes an error.
ex) Root User" '
try
{
if(count($_POST) == 0) throw new \Exception('Form is empty');
$emailTextHtml .= "<table>";
foreach ($_POST as $key => $value) {
// If the field exists in the $fields array, include it in the email
if (isset($fields[$key])) {
$emailTextHtml .= "<tr><th>$fields[$key]</th><td>$value</td></tr>";
}
}
$emailTextHtml .= "</table>";
$mail = new PHPMailer;
$mail->setFrom($fromEmail, $fromName);
$mail->addAddress($sendToEmail, $sendToName); // you can add more addresses by simply adding another line with $mail->addAddress();
$mail->addReplyTo($from);
$mail->isHTML(true);
$mail->Subject = $subject;
$mail->msgHTML($emailTextHtml); //
what should I do?
$fromEmail = 'demo#domain.com';
$fromName = 'Demo contact form'
How should I change it?