everyone can sell ?

Hi,

Yes. You can configure HikaMarket to have every user in a specific user group automatically become a vendor.
You can even use the "User group on registration" setting of HikaShop alongside a custom field of the table "user" to let the user himself choose during the registration if he wants to be a normal user or a vendor and assign it to different user groups based on that:
www.hikashop.com/support/documentation/5....html#checkout_login