How to Vote from China Guide
https://www.amcham-shanghai.org/en/article/how-vote-china-guide
Electronic, E-mail, Fax submissions: Consider that electronic/email submissions will be the fastest way to vote from China, if your state allows it.
If you need to send your election materials to your election official by fax but do not have access to a fax machine, you can email them to
[email protected] and FVAP will fax your election materials for you. This service is for fax submissions only. If your state accepts your election materials by email, you should email them directly to your election official.
Voting by mail: If your state requires you to return ballots by mail, you can do so through international mail, professional courier service, or through the US Consulate’s diplomatic pouch.