Hello,
Vendors can set-up a "terms & condition" in their profile (depending the ACL you configured).
It is also possible to add new vendor custom fields to let them have more than just the "terms & conditions".
It requires some configuration and a view override if you want to have a special display for these elements.
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.