How to return data from a form within the same form?

Question

is there a way that I can use data from a form within the same file without putting the action file on a another file but instead embed the code within the same file the form's code is embedded, since on solo learner I can't use two separate files

Answer 1

<?PHP // form.php
if(isset($_POST)){
// handle form input here
}
?>
<form action="<?php echo $_SERVER["PHP_SELF"]; ?>" >

Answer 2

As Sidharth just posted yes. Everytime you request for a page the browser uses HTTP GET eq $_GET and you can use the same "page" for post. You just need to define the attribute method="post" for the form that actually is missing from the Sidharths example. After that the code inside the if(isset(...)) block in the example gets executed.
for debugging use var_dump($_POST) to see what the post contains.