<?php
$email = "foo@bar.com";
$whatsapp = "";
$html = "<h1>Aqui começa seu HTML</h1>";
if ($email != "") {
$html .= "<strong>E-mail: {$email}</strong>";
}
if ($whatsapp != "") {
$html .= "<strong>WhatsApp: {$whatsapp}</strong>";
}
echo $html;
PD9waHAKCgokZW1haWwgPSAiZm9vQGJhci5jb20iOwokd2hhdHNhcHAgPSAiIjsKCiRodG1sID0gIjxoMT5BcXVpIGNvbWXDp2Egc2V1IEhUTUw8L2gxPiI7CgppZiAoJGVtYWlsICE9ICIiKSB7CiAgICAkaHRtbCAuPSAiPHN0cm9uZz5FLW1haWw6IHskZW1haWx9PC9zdHJvbmc+IjsKfQoKaWYgKCR3aGF0c2FwcCAhPSAiIikgewogICAgJGh0bWwgLj0gIjxzdHJvbmc+V2hhdHNBcHA6IHskd2hhdHNhcHB9PC9zdHJvbmc+IjsKfQoKZWNobyAkaHRtbDs=