If you are a blogger/web publisher, you should constantly be posting links to your social media pages. Facebook is reportedly dropping support for link preview customizing - that is, the changes you can make to your link’s title, meta description and image preview when you sharing links on Facebook.
Starting December 18, 2017, you will not be able to customize links that are not yours. Facebook is primarily doing this to prevent misuse of link customization by users, that results in false information and fake news.
Starting December 18, 2017, you should verify your website’s domains on Facebook Business manager to have the ability to customize your links. You can make use of this domain verification guide from Facebook to add your website domains to Facebook and verify it by adding TXT entry to your DNS records, or by uploading a HTML file to your website’s root directory.
Facebook has detailed description on how you can do this.
When you are done verifying your domain, and associating your Facebook Page to that domain, you are good to go. You will have access to editing your domain’s link previews when you upload links to Facebook.
This applies for posts sent from publishing tools like Buffer and HootSuite too.