How to Claim Magearna for Free in Pokemon Sun and Moon
Magearna is up for grabs indefinitely, but you have to finish the game first.
Pokemon Sun and Moon players can get the mythical pocket monster Magearna, but there are a few steps standing between them and their latest acquisition.
First, complete either Pokemon Sun or Moon. Once you've finished, select the QR Scanner function, center the QR code found below, and press the R button. (You can also find the QR code on the Pokemon website.)
After grabbing the code, head to Hau'oli City and visit the deliveryman at the Antiquities of Ages shop. He'll give you Magearna.
Magearna isn't the only mythical Pokemon hanging around: Meloetta is available in Pokemon X and Y, as well as Alpha Sapphire and Omega Ruby, from December 1st until the 24th.