It is now possible to embed PowerApps into SharePoint Online pages as web parts using iframes. The PowerApps and the SharePoint Site (where the app is to be embedded) need to be part of the same Office 365 Tenancy.

Although an app with mobile layout can be embedded on the SharePoint page, for better usability and look-feel, it is recommended to create an app with tab layout.

I have used the ‘Asset Checkout’ tab layout default template from PowerApps to create the app.

This is not the final version of the capability and it is expected that the Microsoft team will bring in a better way to do this in future.