form for send eMail

mail.php

<?php

$method = $_SERVER['REQUEST_METHOD'];

//Script Foreach
$c = true;
if ( $method === 'POST' ) {

	$project_name = trim($_POST["project_name"]);
	$admin_email  = trim($_POST["admin_email"]);
	$form_subject = trim($_POST["form_subject"]);

	foreach ( $_POST as $key => $value ) {
		if ( $value != "" && $key != "project_name" && $key != "admin_email" && $key != "form_subject" ) {
			$message .= "
			" . ( ($c = !$c) ? '<tr>':'<tr style="background-color: #f8f8f8;">' ) . "
			<td style='padding: 10px; border: #e9e9e9 1px solid;'><b>$key</b></td>
			<td style='padding: 10px; border: #e9e9e9 1px solid;'>$value</td>
		</tr>
		";
	}
}
} else if ( $method === 'GET' ) {

	$project_name = trim($_GET["project_name"]);
	$admin_email  = trim($_GET["admin_email"]);
	$form_subject = trim($_GET["form_subject"]);

	foreach ( $_GET as $key => $value ) {
		if ( $value != "" && $key != "project_name" && $key != "admin_email" && $key != "form_subject" ) {
			$message .= "
			" . ( ($c = !$c) ? '<tr>':'<tr style="background-color: #f8f8f8;">' ) . "
			<td style='padding: 10px; border: #e9e9e9 1px solid;'><b>$key</b></td>
			<td style='padding: 10px; border: #e9e9e9 1px solid;'>$value</td>
		</tr>
		";
	}
}
}

$message = "<table style='width: 100%;'>$message</table>";

function adopt($text) {
	return '=?UTF-8?B?'.Base64_encode($text).'?=';
}

$headers = "MIME-Version: 1.0" . PHP_EOL .
"Content-Type: text/html; charset=utf-8" . PHP_EOL .
'From: '.adopt($project_name).' <'.$admin_email.'>' . PHP_EOL .
'Reply-To: '.$admin_email.'' . PHP_EOL;

mail($admin_email, adopt($form_subject), $message, $headers );

send eMail

html:
<form id="call-back">

			<input type="hidden" name="project_name" value="site">
			<input type="hidden" name="admin_email" value="your e-mail">
			<input type="hidden" name="form_subject" value="theme mail">
			
			<span>call back</span>
			<input type="text" name="Name" placeholder="your name" maxlength="45" required>
			<input type="email" name="e-mail" placeholder="exaple@mail.com" required>
			<input type="tel" name="Telefone" placeholder="+38 (0__) ___ __ __" maxlength="20" required>
			<textarea type="text" name="Content" placeholder="input text"></textarea>
			<button class="bttn">call back</button>
		</form>

js:
	$("#call-back").submit(function() { //Change
		var th = $(this);
		$.ajax({
			type: "POST",
			url: "mail.php", //Change
			data: th.serialize()
		}).done(function() {
			alert("Ваша заявка прийнята.");
			setTimeout(function() {
				// Done Functions
				th.trigger("reset");
				$.magnificPopup.close();
			}, 1000);
		});
		return false;
	});