The eticket usually comes by email within a minute or so of ticketing, though on occasion it has been delayed a bit. If you know the PNR you can look up the remaining details in the website if all else fails.

One of my recently booked tickets KL sent me an email instead explaining that the eticket had been issued but there was a delay in emailing it due to technical issues. Followed within the same minute by the eticket email.