Get from input values

I am learning word press. I have 2 questions

1 Question
How to get my form input values in same page or in another page template


<form id="formId" action="" method="post">
<input style="width:88%" type="text" name="name">
<input type="submit" name="subs" value="Submit" />
</form>


In same fie i put

<?php
if( isset($_POST['subs']) ) {

echo $_POST['name'];
}
?>

i also tried $_SERVER[‘PHP_SELF’]; in action but its not dsiaplying.

When click submit it refreshed and displays “No Results Found”

2 Question.

How to show the submitted values in wp-admin