So you're working on a live application and need to invite another person to join? Just use the 'Stakeholders' features for that.
1/ Click on 'Stakeholders' from the sidebar menu and,
2/ Create a new role describing the person you're about to invite (Eg. assistant)
3/ Then add the person's contact details
4/ Move on to the 'Assignment tab' to select the line items that you'd like to make accessible to your additional stakeholder
Alternatively, you can also assign specific line items to secondary stakeholders directly from the checklist.
In the example below, we clicked on the 'Edit' button of the 'Valid ID' line item. When now, can give access to the spouse and decide whether or not the primary user should see or not the spouse submitted files and vice versa.