How to send mail using php code

<?php
header('Content-type: application/json');
$status = array(
'type'=>'success',
'message'=>'Email sent!'
);

    $name = @trim(stripslashes($_POST['fnm']));
    $name = @trim(stripslashes($_POST['lnm'])); 
    $email = @trim(stripslashes($_POST['email'])); 
    $email = @trim(stripslashes($_POST['subject'])); 
    $message = @trim(stripslashes($_POST['message'])); 

    $email_from = $email;
    $email_to = 'email@gmail.com';

    $body = 'fName: ' . $fnm . "\n\n" . 'lName: ' . $lnm . "\n\n" . 'Email: ' . $email . "\n\n" . 'Subject: ' . $subject . "\n\n" . 'Message: ' . $message;

    $success = @mail($email_to, $subject, $body, 'From: <'.$email_from.'>');

    echo json_encode($status);
    die;
?>