The quickest answer I feel I should give to this question is this: not your handwriting! Scrawling addresses on boxes with a pen is extremely amateurish, and you shouldnt do it. Print your own labels instead. But what should you put on them? The buyers address: This might sound obvious, but you need to make sure the full address is there, including country and zip or postal code https://www.next-t.co.kr/seo/%ea%b2%80%ec%83%89%ec%97%94%ec%a7%84%ec%b5%9c%ec%a0%81%ed%99%94seo%eb%9e%80-%eb%ac%b4%ec%97%87%ec%9d%b8%ea%b0%80/