In testing2.php use the following code to get the name:
if ( ! empty($_POST['name'])){
$name = $_POST['name']);
}
When you create the next page, use the value of $name to prefill the form field:
Name: <input type="text" name="name" id="name" value="<?php echo $name; ?>"><br/>
However, before doing that, be sure to use regular expressions to verify that the $name only contains valid characters, such as:
$pattern = '/^[0-9A-Za-zÁ-Úá-úàÀÜü]+$/';//integers & letters
if (preg_match($pattern, $name) == 1){
//continue
} else {
//reload form with error message
}