As a US citizen, you are required to file a return and pay income taxes on all your world-wide income, even if you don't live in the US. There are certain provisions that modify this, such as a tax credit for foreign taxes you paid, or an exclusion for foreign earned income if you work outside the US for the entire year.
The rules on who is required to file are the same as if you were living in the US. You only need to file a tax return if you taxable income was more than $6000 or $10,000 (for 2013-2017, and depending on whether or not you are your parent's dependent) or more than $12,000 for 2018. Taxable income includes wages, interest and investment income, profits from buying and selling things, and so on. Taxable income does not include gifts or support from a parent.
If you have not had taxable income for those years over the filing limit, you don't need to file income tax returns.
If you own a foreign bank account in your name with more than $10,000 in it, you must file an annual report called an FBAR. This is a reporting requirement, no tax is owed, and it is filed separately from a tax return using a separate IRS electronic system. The FBAR report is also due April 15 of each year.
https://www.irs.gov/businesses/small-businesses-self-employed/report-of-foreign-bank-and-financial-a...
