Once your Date field has been added on the form, in the left side panel you will see different customizations that you can bring to your field. Under Validation, you can:
a) set up conditions from when you accept a date and until when
b) set up accepted days
Setting up conditions: by default, will be set on none, but you can modify them to today-1 week, yesterday, today and so on. Using the custom date option, you can also specify the number of days, weeks, years. This can be accomplished by typing the number and followed by d (days), w (weeks), m (months), y (years) in the custom date box (e.g: +5d, +3m +1w, +2y)
Accepted days: by default, all of them are selected. You can unselect the days that you do not accept.