You can add date fields to your form. You can chose to auto-date a field or provide the user with a calendar tool to choose their own, unique date. 

To Autodate

1. Add a date field where you would like your form to be dated. A date field will appear.

 If a form is sent back to a step for corrections, the previous date will clear and the form will be autodated with the date the form was re-submitted. 

To provide a calendar tool

1. Add a date field where you would like your form to be dated. A date field will appear.

2. Click into the date field to open the grey field settings box. A drop down menu titled "How is the date added?" will appear. If you click on "Calendar tool", the date field will allow users to select a unique date.