This is the easiest way to have your tickets, so that you get them immediately after the purchase and without leaving home. However, if you haven't printed the tickets during the purchasing process you can do it later any time accessing the Print Tickets. Note that if you have selected your tickets to be picked up in stores you won´t be able to change this option.
Remember that once in the premises you might be asked to identify yourself (with the ID card or passport). If your details are different from the customer that purchased the tickets you will be denied access.