The second one "我要把这个包裹寄美国去" is correct. Should be similar to how we'd say it in English in this case. It means "I want to have this package sent to the States." or "I want to send this package to the States" Hope this helps.

您好，Chris 语法对不对? 往 can be used as a verb and a preposition. These are several samples of 往 as a preposition: (1) 往 used to indicate the direction of an action. It used with an adverb of place, and placed before the verb. i.e.: - 往南边走 (to walk towards the south)        - 往西边飞 (to fly towards the west) (2) 往 can be also placed after a few of verbs, such as 开，飞，送，寄，逃. i.e.: - 车开往城里去 (the bus goes to town) - 他们飞往美国去了  (They flew to the US) Hope they help. Please do not hesitate to ask me, if you require further question. 敬上， Tere

Alan is right. The second one is correct. The first one is actually wrong. Just to add to his answer, depending on your situation, you could also say: 我想/得把这个包裹寄去美国。

but there is 往 direction........ how do you use this grammar point

你好Chris， “我要把这个包裹寄美国去”更好一些，但是这个句子有一点问题，It should be : 我要把这个包裹寄到美国去。 “往美国这个包裹寄去”------往美国寄去这个包裹。 希望对你有帮助~Thanks~