<form action = "test.php" method = "post">
<input name = "name"><br>
<input name = "age">
<input type = "submit">
</form>

<?php
if($_SERVER['REQUEST_METHOD']=='POST'){
$name = trim(strip_tags ($_POST ['name']));
$age = abs((int)$_POST['age]);
echo 'Ваше имя: '  . $name;
echo 'Ваш возраст : '  . $age;
}
?>