I'm a resident of California and will be starting a company this year but will not be living in California as I'm teaching English in China.
So that means I don't have a address in the USA to start register a DBA and start a company.
What should I do?
I would recommend you speak with a CA corporate attorney or CPA re: business formation and tax liabilities for a CA resident located abroad. If you are a resident of CA, most likely you will need to file in CA irrespective of your current location, but ask an expert to find out for sure.
Do you have family in the US who your comfortable sending your business mail to?
From my understanding it's not too difficult to change the listed address later once you return to the US, but I would ask about this beforehand.