请英语高手帮我看一看下面这句中译英是否正确

You may ask(entrust) your representative to handle (可省略'who is able')the appliaction procedures on your behalf, but he (she) must have a letter of attorney from you.

* 用 'entrust' 比较恰当,因后句涉及'委任状'(法律上的要求)
** handle...on your behalf (为你代办)

正确。

You can entrust your agent to agent application procedures for you, but you must have your certificates of appointment

楼主用电脑更多的是考虑一种解决问题的思想，
可以通过百度，GOOGLE这类搜索
关键字如：翻译，在线翻译，免费在线翻译之类的
只作为参照，楼主感觉不合适的地方可以再修改下，
最后祝楼主答题开心，解决好此问题！

可以

不过who is able 没必要

申请手续是中文说法，英文只要写成application即可，没必要加procedure

句子尽量简单明了即可

You may ask your representative to submit the letter of attorney for your application.