I had the names and addresses for the New Year’s cards printed.
「年賀状の本文だけでなく、宛名も印刷してもらいました。だから、メッセージだけ手書きするつもりです」は英語で「I asked them to print not just the body of the New Year’s card, but also the address. That way I only have to handwrite the message.」という表現が良いと思います。