Auto bidding is nothing but bids automatically on auctions.
User can place auto bid before auction ends for the product you are intrested in by updating details such as choose product, max bid count, and auto bid start price.
so if you set an auto bid on auction, users no need to keep on watching an auction and your bid will be placed automatically when the time time reaches evn though you are offline before auction ends and by this way user may win an auction.
Once auto bid was set up, users have an option to update auto bid and stop auction at any time.