Head to your Settings, then Booking fields, then scroll down to the Booking details section:
If you'd like to add these to all of your entries, select Edit, Add to all entries, then Update field:
You can also add attachments to these fields, perfect for privacy policies.
To do this, select Upload under the Attachment heading to upload your file, or choose an existing uploaded file using the drop-down menu:
If you head over to your Bookings tab, you can download attendances (by selecting Options).
You'll be able to see which bookers have consented to which field. You can also view this data on the Customer list.