During July-August 2019, new page authoring improvements were rolled out to SharePoint Modern pages. Following are the features which this video explains about -

• On-Page Anchors
• Vertical Sections
• Link Previews

 

 

At the time of recording this video, these features were being rolled out to first release tenants and then, to the standard tenants. If you do not see these in your tenant yet, you will be getting them soon.