The buyer cannot decide if he wants to buy the item on EMI, It is the seller who decides if he wants to sell the item on EMI.
If the seller does not have the EMI option for the item that you want, you can always make a request through "contact seller" and request him to list the item with EMI option. The choice is his anyway and the buyer cannot do anything about it.
There are many banks who readily convert your CC purchase into interest free EMI's you can always approach your bank for more details before you buy the product.
Just follow the payment instructions and if there is an EMI option (see below) then there will be a check the box for EMI, just put a tick mark in it and click the continue button that's it. When you take a final print of the order placed you will get the remark that the item is purchased on 3 or 6 EMI's.
PS: EMI option is only valid with or for ICICI bank credit cards and not any other card.