Can humans use god ki? In Dragon Ball Super, Battle of Gods and Resurrection 'F', gods of destruction, beings belonging to Whiss's race (some sort of angels or angels), supreme kais and super saiyan gods can use "god ki". In DBS and Resurrection 'F' also, others no super saiyan gods saiyans like Vegeta can obtain the power of god ki without transforming into super saiyan god by training (and also becoming super saiyan god super saiyan by transforming) . Can other Dragon Ball races like humans or namekians or  Frost Demons obtain god ki by training too?
Simply yes, not only humans, all mortals could obtain or use god ki via various ways:


Through special rituals, such as Super Saiyan God Ritual. Unfortunately this kind of rituals don't exist throughout human history, but maybe it do exist in other races.
Highly intense training under the supervision of an angel, for example Whis. It's most likely to obtain god ki by entering the Hyperbolic Time Chamber.


(Source)