Is possible to post the same listing on two categories?

Imagine a page with all listings on the website and another for the specific listing category, there is some code snippet to when user create a listing this listing is posted in two pages?

Or there is some shortcode to show the last listings from one parent category?

Unfortunately, there’s no way to assign a listing to multiple categories because many features and options require a distinct category to be set per listing (e.g. category-specific attributes). You can set multiple categories via the back-end but there may be unpredictable issues.
If you mean sharing the same listing on multiple websites this may be possible with WordPress Multisite installation.