I want to transfer 20 Gold E-Cards of Plan 3/3 A do I have to send them one by one?

You will find a window on Gold E-Card bank page where you can mention Gold E-Cards quantity simply fill in the number of cards you want to transfer and click Select E-Card mentioned number of cards would be checked and selected automatically, in next window fill in the GA and GA ID of the person you are transferring card to and click Send E-Cards.