Here is the Kunming address I had the best luck with:

Jiang Dong Si Ji Gong Yu, Apt 1708
Beijing Lu, Panlong District, 650224
Kunming, Yunnan, P.R. China
————————————————————————

650224
中国云南省昆明市盘龙区北京路江东四季公寓1708 室
电话：18669888888

Stuff was sent US mail and took about two weeks. The English was to get it going in the right direction. The Chinese address in Hanzi is correct with a phone number. Customs will call if necessary. These days you get a US tracking number but it was useless in China

I gave up on FEDEX as it was left in the university mail room with a few hundred other FEDEX packages in a big pile.

+1 what geezer said.

Use both english and Chinese in that format.

Add your contact China phone number in case customs or delivery has questions.

Email or message the info to your friends and have them print it out.

Then cut and paste it on the box.

I made labels to stick on US Mail forms.

US Mail was cheaper and easier to use than FEDEX

Hope this helps