We have a standard set of information we require from the guest during checkout and quote acceptance. Sometimes you want to grab additional info specific to your situation or properties, like names of all guests or types of beds to have a available. We've always had custom fields, but we've recently added the capability to let guests fill out booking custom fields during checkout.
To do that, add a new custom field (in the Settings > Custom Field Definitions section):
If you turn Display on under the Quote Acceptance section there, the guest will see that field during checkout and be able to enter data or required to enter it based on what you set here.
Once the guest completes checkout and the booking is created, you can review the values the guest entered:
Because these are custom fields, you can also use that value as a mail merge field in renter agreements or email templates: