Audience Insights in Facebook
Audience Insights is a Facebook tool that lets you explore and learn more about your target audiences — saved audiences, custom audiences, or just any targeting combinations.
Read more on Facebook: Use Audience Insights
Audience Insights in Smartly.io
Facebook has deprecated access to audience insights through the API, and they cannot be accessed in Smartly.io anymore. To view audience insights, use the Facebook Audience Insights tool.