Related Questions:
Where can I choose my Document Due Date?
Why is the Due Date on my Document blank?
Can I add a Duet Date to a Document I've already created?
Answer:
When Creating a New Document
When creating a Document you are able to choose the Document due date from the creation page.
When Adding to an Existing Document
You can also add in a Due Date once the Document has already been created. This can be done from the Document info tab when the Document is open.
Important! Clients can still sign Documents when they are past their Due Date!