I want to echo message when form is submitted - php

Question

I'm not very good at PHP (more of a front-end developer) and I'm doing a website for a client. I got everything working up to now except for one thing. When the user fills out the contact form and submits it successfully i want to display a message that tells them the email was sent. I already have the div set up I just don't know who to execute it with PHP.
<div class="sent">Email has been sent.</div>
<form action="" method="POST" class="contact-form">
<img class="close" src="images/close-icon.png">
<div class="top-title">Contact Us</div>
<input type="hidden" name="action" value="submit">
<div class="input-title">Name*</div>
<input class="input" name="name" type="text" value="" size="30" required><br>
<div class="input-title">Phone Number*</div>
<input class="input" name="phone" type="text" value="" size="30" required><br>
<div class="input-title">Email Address*</div>
<input class="input" name="email" type="text" value="" size="30" required><br>
<div class="input-title">How did you hear about us?</div>
<input class="input" name="company" type="text" value="" size="30"/><br>
<div class="input-title">Let us know how we can help you</div>
<textarea class="textarea" name="message" rows="7" cols="30"></textarea><br>
<div class="required">*Fill is required</div>
<input class="submit-button" type="submit" value="Send Email"/>
</form>
<?php
{
$name=$_POST['name'];
$email=$_POST['email'];
$phone=$_POST['phone'];
$company=$_POST['company'];
$message= "\r\nName: " . $_POST['name'] ."\r\nPhone Number: ". $_POST['phone']."\r\nEmail: ". $_POST['email'] ."\r\nHow you know the company: ".$_POST['company'] ."\r\nReason for message: ".$_POST['message'];
$from="From: $name<$email>\r\nReturn-path: $email";
$subject="GS Website Message";
mail("name#email.com", $subject, $message, $from);
}
?>

Answer 1

Change: (and using a conditional statement)
mail("name#email.com", $subject, $message, $from);
to:
if(mail("name#email.com", $subject, $message, $from)){
$sent = "Message sent";
}
Then modify:
<div class="sent">Email has been sent.</div>
to read as:
<div class="sent"><?php if(!empty($sent)) { echo $sent; } ?></div>
Seeing you're new to PHP/forms, it's best to also check if your inputs are empty or not, otherwise you risk in either not getting mail, or receiving empty data.
http://php.net/manual/en/function.empty.php
Set inside a conditional statement also.
I.e.: using NOT empty: ! is the NOT operator in PHP.
if(!empty($_POST['var'])){...}
Edit:
The logic needs to be reversed.
First, place your PHP above your HTML form.
I also added a submit name attribute to your submit button, with a conditional statement and a ternary operator in the div.
<?php
if(isset($_POST['submit'])){
$name=$_POST['name'];
$email=$_POST['email'];
$phone=$_POST['phone'];
$company=$_POST['company'];
$message= "\r\nName: " . $_POST['name'] ."\r\nPhone Number: ". $_POST['phone']."\r\nEmail: ". $_POST['email'] ."\r\nHow you know the company: ".$_POST['company'] ."\r\nReason for message: ".$_POST['message'];
$from="From: $name<$email>\r\nReturn-path: $email";
$subject="GS Website Message";
if(mail("email#example.com", $subject, $message, $from)){
$sent = "Message sent";
}
}
?>
<div class="sent"><?php echo isset($sent) ? $sent : ''; ?></div>
<form action="" method="POST" class="contact-form">
<img class="close" src="images/close-icon.png">
<div class="top-title">Contact Us</div>
<input type="hidden" name="action" value="submit">
<div class="input-title">Name*</div>
<input class="input" name="name" type="text" value="" size="30" required><br>
<div class="input-title">Phone Number*</div>
<input class="input" name="phone" type="text" value="" size="30" required><br>
<div class="input-title">Email Address*</div>
<input class="input" name="email" type="text" value="" size="30" required><br>
<div class="input-title">How did you hear about us?</div>
<input class="input" name="company" type="text" value="" size="30"/><br>
<div class="input-title">Let us know how we can help you</div>
<textarea class="textarea" name="message" rows="7" cols="30"></textarea><br>
<div class="required">*Fill is required</div>
<input class="submit-button" type="submit" value="Send Email" name="submit"/>
</form>

Answer 2

$password=md5($_POST ['password']);
$password3 =md5($_POST ['password2']);
if($password != $password3)
{
$message = "Passwords do not match";
}
etc.
you need add
<form>
<div class="form-group">
<input type="password" name="password" id="password" class="form-control" placeholder="Password *" value="" required/>
</div>
<div class="form-group">
<div class="message"><?php if(!empty($message)) { echo $message; } ?></div>
<input type="password" name="password2" class="form-control" id="password2" placeholder="Confirm Password *" value="" required/>
</div>
</form>