<form method="POST" action="#">
<input type="radio" id="customRadio1" name="customRadio" value="1" class="custom-control-input">
<label class="custom-control-label" for="customRadio1">Activo</label>
<input type="radio" id="customRadio2" name="customRadio" value="0" class="custom-control-input">
<label class="custom-control-label" for="customRadio2">Inactivo</label>
<input type="submit" value="Enviar"/>
</form>
<?php
if(isset($_POST['customRadio'])) {
if($_POST['customRadio'] == "1"){
echo "Activo";
}else {
echo "Inactivo";
}
}
?>