The SharePoint Add-ins on modern pages is a new Office 365 feature. You’ll begin seeing this new feature today.
How does this affect me?
When creating modern pages – for example, the pages within team sites that are connected to Office 365 Groups – you will now be able to use app parts from SharePoint Add-ins. The app parts from SharePoint Add-ins that are already installed on the site where the page is being created will now appear in the modern page toolbox.
What do I need to do to prepare for this change?
There is nothing you need to do to prepare for this change. Please click Additional Information to learn more.