When you have a document ready to be sent, you can define the expiration date and how many times you want the recipient to receive reminders in case they haven't signed the document.
In the last step before sending the document, you will see a section called Advanced Options:
Click on Edit to define your preferences for reminders and expiration date:
The fields that you select will be filled with a ✓ and will be saved automatically. The preferences that you choose in this step will always be specific to the individual document that you are sending at that moment.