While The Masters is still, technically, in invitational, the invites today are based on a series of qualifying criteria. Any golfer who meets the criteria gets invited. But Augusta National still mails out old-fashioned paper invitations to golfers who've qualified.
On Twitter today, one such golfer had this to say:
Gonzalo Fernandez-Castano included a photo of the invitation he received from Augusta National, to play in the 2014 Masters: