Webmasters – Sharing – Documentation – Facebook for Developers

To see how your markup appears to the Facebook Crawler enter a URL into Sharing Debugger. It will show which meta tags the crawler scrapes as well as any errors or warnings. The debugger also triggers a scrape of your page, so if you do have errors in your HTML you can use the debugger to update your content. See Updating Objects to learn more.

https://developers.facebook.com/docs/sharing/webmasters