Windows Domain Join is a feature that lets users establish a remote and secure connection to a work domain using credentials from the enterprise, allowing them to effectively "join" that domain.
Windows Domain Join was introduced in Windows 7 and can still work even if there is no immediate connection. The offline domain join feature eases the deployment of desktops in large enterprises.In Windows Server 2008 R2, a command called Djoin.exe was introduced so administrators could have an easier time running Windows Domain Join. The Windows Domain Join feature received an upgrade with release of Windows Server 2012 R2. The upgrade is called Workplace Join.