Available with Workflow Manager license.
Obtaining a license
ArcGIS Workflow Manager uses your current ArcGIS license system and requires authorization to be activated. You will need to update your license manager to add the Workflow Manager feature. Once your license manager has been updated, you will be able to use the Workflow Manager applications and features.
Upgrade your license files for desktop
Refer to the ArcGIS Desktop help for more information on obtaining a license and authorizing ArcGIS Desktop extensions.
Upgrade your license files for server
Refer to the ArcGIS Server help for more information on authorizing ArcGIS Server extensions feature.
Uninstalling previous Workflow Manager products
If any ArcGIS products are installed on your machine and are earlier releases to 10.5.1, they need to be updated to 10.5.1 before proceeding with the ArcGIS Workflow Manager for Desktop setup. The ArcGIS 10.5.1 Workflow Manager setup package is designed to detect and upgrade an existing installation of ArcGIS Workflow Manager for Desktop.
The Workflow Manager setup will terminate and display a dialog box if conflicting releases of these products exist on your machine. If so, you must uninstall each of them and run the ArcGIS Desktop setup again to proceed with your installation.
As long as all the installed products are for the 10.5.1 release, they can coexist on your computer without conflict.