When you place bid your ebay items Will they ask your credit card at first I accidentally place bid but how come they didn't ask my credit card and i still see the increase bid one?

They do not ask for your credit card info to place a bid on EBay. If you accidently placed a bid you should try to contact the seller to see if they will let you cancel your purchase. If they will not, then you will have to pay for the item if you are the highest bidder.