Do you mean that you are a U.S. citizen who left the U.S., moved to another country, and live in the other country? If you are a U.S. citizen you are subject to the same tax filing requirements as citizens who live in the U.S., no matter where you live. For how many years have you had income and not filed a U.S. tax return?
You can use the tool at the following link on the IRS web site to see if you are required to file a U.S. tax return.
Do I Need to File a Tax Return?
