Player’s international positions items were released for the first time ever in FIFA 16, during the FUT anniversary.
Original players cards are usually released when FUT starts in their natural positions. In other words, the positions of their regular cards are the ones where they usually play for their clubs. International position changes are regular not in form cards in which the players have the positions where they play for their national teams. That's the only difference. Ratings and stats are exactly the same.
These cards are released for a limited time, usually a week, replacing the respective regular card during that period. If someone own the original regular card, they will keep unchanged. If he wants the 'improved' version, he will need to buy the corresponding version in the market or pull it from a pack.