我理解是在中國填好表格寄回美國東部移民局，廣州不受理對嗎？
-Correct.
哪回寄如果填中國的地址嗎？還是送郵件不需要郵寄？
我可以讓在美國的家人幫我寄嗎？回寄美國的地址？
-You do not need to have a reason to abandon your green card. You can file I-407 within US using your address in US. Then, leave US after you file I-407. You had better leave US before your I-407 is approved and thus, you do not have a unlawful presence problem. Your family can receive the correspondences from USCIS for you.
See this link for I-407 filing in US (Read I-407 Instructions carefully and provide all the required documents for I-407 filing):
Record of Abandonment of Lawful Permanent Resident Status | USCIS
謝謝！
