This is where my upload.php is located
xampp/htdocs/site/admin/upload.php
I want to upload images to this address
xampp/htdocs/site/img
I am using this code by W3schools in upload.php
I need to change this code in upload.php file, but confused, what is my img folder address
$target_dir = "img/";
What to write in this ^^^^^^
Use ../img/.
.. means the parent directory, so going from xampp/htdocs/site/admin/ to xampp/htdocs/site/. From here, you just need the img/ directory.