আপনি can either meet him in person at a convention/wherever you're capable of meeting him at অথবা buy his autograph online (wouldn't recommend that, though - could be faked/it's not as nice as meeting the person and getting the autograph in person).
Somtimes আপনি meet the person at a masive place where all the celebs go to give autographs and after আপনি give an auto graph u take a picture and smile.