ArcGIS Pro 2.7 API Reference Guide
ArcGISPortal Class
Members 

ArcGIS.Desktop.Core Namespace : ArcGISPortal Class
The ArcGISPortal class is part of the Pro Portal API which provides a way to build applications that work with content from ArcGIS Online or an ArcGIS Portal. ArcGIS Portal is software technology from Esri that customers can deploy either on premise or in the cloud. ArcGIS Online is Esri's Software as a Service offering that represents GIS as a Service and is implemented using the same technology as ArcGIS Portal. The Portal API allows application developers to work with users, groups and content hosted within ArcGIS Online or within an ArcGIS Portal.
Object Model
ArcGISPortal ClassSignInResult Class
Syntax
public class ArcGISPortal 
Public Class ArcGISPortal 
Remarks
ArcGISPortal instances are instantiated using the ArcGISPortalManager and its ArcGISPortalManager.AddPortalAddPortal method.
Note: out of the box you will always have a portal defined for arcgis.com (ArcGIS Online)
Inheritance Hierarchy

System.Object
   ArcGIS.Desktop.Core.ArcGISPortal

Requirements

Target Platforms: Windows 10, Windows 8.1

See Also

Reference

ArcGISPortal Members
ArcGIS.Desktop.Core Namespace