In WordPress, there is a one function name called wp-cron. It is placed in the root path of your website with the name wp-cron.php. It is a kind of run cron job for making below.

> Checking Plugins & Themes Update.
> Publishing scheduled posts.
> Sending pingback and etc.

This cron runs in every time whenever a page is a load. And will check all scheduled events needs to be done at the moment.

Learn more… Why wp-cron.php disabled in Shared Hosting?