For what reason can open server stop interpreting php script?

Question

PHP

Some time ago I installed WordPress, I thought about doing something. Postponed the case for months. Here it is useful again, I thought to continue mastering it, but for some reason the server does not process the code, but displays it in the browser. I tried running other php files, NOT wordpress, it's just that my php tutorials are the same.
In the server settings - PHP 7.2, Apache, MySQL ... I'm not special yet, so I don't understand what happened.
How I launch it: in the address bar I go to the localhost folder, select the desired folder of the site with WordPress and launch index.php. Well, other files follow the same pattern.
Are there any considerations?

Answer 1

Is the openserver flag green? Red?
The code in the browser is displayed when php is not running.