How to only send the content without tags?

I'm using the following code to send an email using a html template. 

The email is sent but in the email body I get all the HTML tags also (`<div>`, `<p>`.. and so on). 

```
    $message    =   array();
    $message['id'] = $booking_id;
    $message['name'] = $order_info[0]->name;
    $message['email'] = $order_info[0]->email;
    $message['address'] = $order_info[0]->address;
    $message['phone'] = $order_info[0]->phone;
    $message['guests'] = $order_info[0]->total_guest;
    $message['summary'] = $order_info[0]->summary;

    $email_to   =   self::has_get_settings('email');
    $subject    =   "New Booking! - Booking ID. " . $booking_id;
    $from       =   $order_info[0]->email;
    $from_name  =   $order_info[0]->name;

    $template = file_get_contents($controller->plugin_path . 'includes/libraries/email_template.html');

    foreach($message as $key => $value)
    {
        $template = str_replace('{{ '.$key.' }}', $value, $template);
    }

    $headers    =   'From: ' . $from_name . '<' . $from . '>' . "\r\n";
    $headers    .=  'Reply-To: ' . $from_name . '<' . $from . '>';

    wp_mail($email_to,
            $subject,
            $template,
            $headers);

```