Hi,
Order custom fields are available in HikaShop Business.
But HikaShop have a terms & condition option, available in all edition, where the user have to check the box to continue the checkout.
It is a step that you have to add in your checkout workflow. You can customize the text (using language override).
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.