How to include php file to wordpress theme(index.php)

Question

I would like to include cars.php file to index.php theme; the cars.php file is script, which loads data from the server and works as booking system, when I am trying to connect as usual way include('/.cars.php'); , and check the source code in browser, its there, but no forms appear.

Could be the problem with wordpress engine itself?

Answer 1

I think you have a typo include('/.cars.php'); is likely include('./cars.php');

What you have now would look in the root directory for a file called .cars.php