How to do it?

[Viktor33]

I wanna to write app that would be able to add links into the webdirectories (on PHP). Do u have any recommendations?

[djr33]

That is very unclear.

PHP scripts aren't "apps", but rather "scripts". They're just code... not standalone programs.

Umm....
<?php
echo '<a href="stuff">';
?>

That's it.

If you mean to show all possible directories to create a tree of paths to go on, then that's more complex. Just learn the language, use php.net for help with specific functions, and play with it. Shouldn't be too complex.