In Map Activities to Forms, there are two ways of mapping an activity. Mapping to External Form is the second way. This feature allows one to map a process's activity to a page hosted externally outside of Joget Workflow.

When an assignment is opened by the assignee from the Inbox, instead of viewing the usual Joget Workflow's form, a iFrame will be shown pointing to the External Form defined in the activity mappings. A number of useful information about the assignment will be passed over as request parameter when the iFrame is loaded.

Parameters that will be passed into external form from Joget Workflow:
appId