mojonek

Thx for helping me and advice.

This is my solution

Add this code in to file: simple.php

<?php
if ( is_user_logged_in() ) {
	echo 'user_logged';
?>

<form class="cart" method="post" enctype='multipart/form-data'>
...
</form>

<?php
	} else {
	echo 'user_not_logged.';
}
?>

Thank you for your reply but I still do not know how to do it.
How to hide the “buy” button
I need the code.

I found this example: Function Reference/is user logged in
Display different output depending on whether the user is logged in or not.

<?php
if ( is_user_logged_in() ) {
	echo 'Welcome, registered user!';
} else {
	echo 'Welcome, visitor!';
}
?>

But still need help 🙁
How to put this code into “buy” button?