I have a PHP script to send emails with this code- - php

Question

I have this PHP code to send emails.
<?php
if (isset($_POST['ajax'])) {
$to = $_POST['to'];
$subject = $_POST['sub'];
$msg = $_POST['msg'];
$headers = "MIME-Version: 1.0" . "\r\n";
$headers .= "Content-type:text/html;charset=UTF-8" . "\r\n";
$headers .= "From: ".$_POST['name']."<".$_POST['from'].">";
$send = mail($to,$subject,$msg,$headers);
if ($send) {
echo "<p id='success'>✔️ $to</p>";
}else{
echo "<p id='error'>❌ $to</p>";
}
exit();
}
?>
I want to integrate it with the following form.
<form>
<input id="input-1" type="text" placeholder="John Doe" required autofocus />
<label for="input-1">
<span class="label-text">Full Name</span>
<span class="nav-dot"></span>
<div class="signup-button-trigger">Sign Up</div>
</label>
<input id="input-2" type="text" placeholder="john" required />
<label for="input-2">
<span class="label-text">Username</span>
<span class="nav-dot"></span>
</label>
<input id="input-3" type="email" placeholder="email#address.com" required />
<label for="input-3">
<span class="label-text">Email</span>
<span class="nav-dot"></span>
</label>
<input id="input-4" type="text" placeholder="●●●●●●" required />
<label for="input-4">
<span class="label-text">Password</span>
<span class="nav-dot"></span>
</label>
<input id="input-5" type="text" placeholder="●●●●●●" required />
<label for="input-5">
<span class="label-text">Confirm Password</span>
<span class="nav-dot"></span>
</label>
<button type="submit">Create Your Account</button>
<p class="tip">Press Tab</p>
<div class="signup-button">Sign Up</div>
</form>
Is there a way to make it work. I want to use the PHP GET method. Is this possible? How would I get around doing that?
I want to send a PHP GET request, which would then send the email. Do I have to change anything in the form? In the PHP?