PowerApps Portals Is Now Available

Microsoft rolled out the public preview for PowerApps Portals. A service for building custom business apps that connect to your data and work across the web and mobile.

Recently, Microsoft announced the public preview for PowerApps Portals, which is a new capability coming to PowerApps, and was first introduced during Microsoft Business Application Summit last month.
Source: Microsoft 
The company said that PowerApps Portals will enable you to create and manage a new App type called "Portal" for your Common Data Service and Dynamics 365 environments directly from make.powerapps.com. This will also give you access to all the Portals present in your environment in the apps list.
key capabilities that PowerApps Portals brings enables you to engage with your customers and partners, build websites easily with a new dedicated portal designer, integrate with Microsoft services to enrich content and model complex business process using pro dev extensibility.
Also, PowerApps Portals, allows you to extend Dynamics 365 Customer Engagement Applications using prebuilt templates and gives you advanced administration capabilities.
The company said that PowerApps Portals preview is enabled automatically and by-default for all PowerApps Customers. You can directly login to PowerApps Studio and get started on creating a Portal.