https://www.theguardian.com/technology/ng-interactive/2017/oct/25/revealed-how-australians-are-targeted-with-political-advertising-on-facebook

This database shows posts that organisations and individuals have paid to push into Facebook news feeds.

Unless you are the one targeted, there is no way know that these posts appeared as ads, which is why Guardian Australia has partnered with ProPublica to track and publish them.