The Manual Activity is used to launch work items on a workflow (either via Save and Send or an automated step using the CreateWorkItem BIC or SQL Create Work Item BIC. It is also used for any step in the workflow requiring manual intervention by a user.
The Details tab in the Manual Activity must identify the user or role (recommended) that is responsible for initiated the work item or responding to an active work item:
If the work item is anchored to a repository record, then editing that record in Enable will provide access to the Manual Activity: