<html>
<head>
<title>Feedback page 1</title>
</head>
<body>
<form action="post_send.php">
<input type="hidden" value="Feedback page 1" name="subject">
<textarea name="body"></textarea>
<button type="submit">Отправить</button>
</form>
</body>
</html>
<html>
<head>
<title>Feedback page 2</title>
</head>
<body>
<form action="post_send.php">
<input type="hidden" value="Feedback page 2" name="subject">
<textarea name="body"></textarea>
<button type="submit">Отправить</button>
</form>
</body>
</html>
<html>
<head>
<title>Feedback page 3</title>
</head>
<body>
<form action="post_send.php">
<input type="hidden" value="Feedback page 3" name="subject">
<textarea name="body"></textarea>
<button type="submit">Отправить</button>
</form>
</body>
</html>
<?php
$subject = $_POST['subject']; // заголовок письма
$body = $_POST['body']; // тело письма
//дальше отправляешь на почту как тебе удобно, через mail() или PHPMailer
?>
<?php
$user_data = [
'login' => '',
'name' => '',
'comments' => [
[
'post_id' => '',
'comment_id' => '',
'comment_text' => '',
],
[
'post_id' => '',
'comment_id' => '',
'comment_text' => '',
],
[
'post_id' => '',
'comment_id' => '',
'comment_text' => '',
],
],
];