Send contact form data to email - php

Question

My goal is to make a contact form, where the user would type their name, email and message. The moment they press "Send", me, as the admin, would receive an email with all the information that was typed in before. Right now the email is sent but its empty, for example:
Reply to:
User name:
User email
User message
Also, when I click on "Send message" it gives me the same form but without CSS, there must be a code mistake which I don't know what it is.
// Form contactos.php
<div class="col-md-7 mb-5 site-animate">
<form action="index.php?cmd=contform" method="post">
<div class="form-group">
<label for="name" class="sr-only">Name</label>
<input type="text" class="form-control" id="NomeM" placeholder="Nome">
</div>
<div class="form-group">
<label for="email" class="sr-only">Email</label>
<input type="text" class="form-control" id="EmailMen" placeholder="Email">
</div>
<div class="form-group">
<label for="message" class="sr-only">Messagem</label>
<textarea name="message" id="Mensagem" cols="30" rows="10" class="form-control" placeholder="Escreva a sua mensagem"></textarea>
</div>
<div class="form-group">
<input type="submit" name="submit" class="btn btn-primary btn-lg" value="Enviar Mensagem">
</div>
</form>
</div>
//File contform.php
<?php
$sql="select * from Mensagem ";
$res=$lig->query($sql);
$lin = $res->fetch_array();
$NomeM = $_POST['NomeM'];
$Email = $_POST['EmailMen'];
$Mensagem = $_POST['Mensagem'];
$email_from = 'admin03#happygreen.pt';
$email_subject = "New Form Submission";
$email_body = "User Name:" .$lin['NomeM']."\n".
"User Email:".$lin['EmailMen']."\n".
"User Message:".$lin['Mensagem']."\n";
$to = "filipajoao1933#gmail.com";
$headers = "De: $email_from \r\n";
$headers .= "Responda a: ".$lin['EmailMen']."\r\n";
mail($to,$email_subject,$email_body,$headers);
header("Location: Contactos/contactos.php");
?>

Answer 1

Form fields (input, select, textarea) need a name attribute you can reference in PHP, yours only have ids. Also, the for attribute in labels reference the id of a form field:
// Form contactos.php
<div class="col-md-7 mb-5 site-animate">
<form action="index.php?cmd=contform" method="post">
<div class="form-group">
<label for="NomeM" class="sr-only">Name</label>
<input type="text" class="form-control" name="NomeM" id="NomeM" placeholder="Nome">
</div>
<div class="form-group">
<label for="EmailMen" class="sr-only">Email</label>
<input type="text" class="form-control" id="EmailMen" name="EmailMen" placeholder="Email">
</div>
<div class="form-group">
<label for="Mensagem" class="sr-only">Messagem</label>
<textarea name="Mensagem" id="Mensagem" cols="30" rows="10" class="form-control" placeholder="Escreva a sua mensagem"></textarea>
</div>
<div class="form-group">
<input type="submit" name="submit" class="btn btn-primary btn-lg" value="Enviar Mensagem">
</div>
</form>
</div>
And your $email_body should be:
$email_body = "User Name:" .$NomeM."\n".
"User Email:".$EmailMen."\n".
"User Message:".$Mensagem."\n";