Yes, if you are a U.S. citizen or a resident alien living outside the United States, your worldwide income is subject to U.S. income tax, regardless of where you live. However, you may qualify for certain foreign earned income exclusions and/or foreign income tax credits.

Yes. You have to file a U.S. income tax return while working and living abroad unless you abandon your green card holder status by filing Form I-407, with the U.S. Citizen & Immigration Service, or you renounce your U.S. citizenship

The due date for filing a federal individual income tax return generally is April 15 of each year if your tax year ends December 31st. 

If the due date falls on a Saturday, Sunday, or legal holiday, the due date is delayed until the next business day. If you cannot file by the due date of your return, you can request an extension of time to file. To receive an automatic 6-month extension of time to file your return, you should file Form 4868, Application for Automatic Extension of Time to File U.S. Individual Income Tax Return, by the due date of your return.

However, if you are a U.S. citizen or resident alien, who is either: (1) living outside of the United States and Puerto Rico and your main place of business or post of duty is outside of the United States and Puerto Rico; or (2) in military or naval services on duty outside of the United States and Puerto Rico on the due date of your return, you are allowed an automatic 2-month extension until June 15 to file your return and pay any tax due.

You must file a federal income tax return for any tax year in which your gross income is equal to or greater than the personal exemption amount and standard deduction combined. However, for tax years beginning after December 31, 2017, taxpayers (including aliens and nonresident aliens) cannot claim a personal exemption deduction for themselves, their spouses, or their dependents.

Generally, you need to file returns going back six years. This will depend on the facts and circumstances of your particular situation.

There are various options for paying your U.S. taxes, some involve processing fees.

1. Direct Pay with Bank Account
2. EFTPS (Electronic Federal Tax Payment System).
3. Federal Tax Collection Service same-day wire transfer). 
4. Check or money order. 
5. Credit or debit card. 

In general, if you are a U.S. citizen or resident alien married to a nonresident alien, you are considered “Married Filing Separately” unless you qualify for a different filing status. If you pay more than half the cost of keeping up a home for yourself and a qualifying child or other relative, you may qualify for the head of household filing status.

If you are a U.S. citizen or resident alien married to a nonresident alien, you and your spouse can choose to have your spouse treated as a U.S. resident for all U.S. federal income tax purposes. This allows you and your spouse to file a joint return, but also subjects your nonresident alien spouse’s worldwide income to U.S. income tax.

In general, you can claim exemptions for individuals who qualify as your dependents. To be your dependent, the individual must be a U.S. citizen, U.S. national, U.S. resident alien, or a resident of Canada or Mexico for some part of the calendar year in which your tax year begins.

Children usually are citizens or residents of the same country as their parents. If you were a U.S. citizen when your child was born, your child generally is a U.S. citizen. This is true even if the child's other parent is a nonresident alien, the child was born in a foreign country, and the child lives abroad with the other parent.

You must include on your return the Social Security number (SSN) of each dependent for whom you claim an exemption. If your dependent is a nonresident alien who is not eligible to get a Social Security number, you must list the dependent's individual taxpayer identification number (ITIN) instead of an SSN.

For tax years beginning after December 31, 2017, taxpayers (including aliens and nonresident aliens) cannot claim a personal exemption deduction for themselves, their spouses, or their dependents.

As a green card holder, you generally are required to file a U.S. income tax return and report worldwide income no matter where you live.

However, if you surrender your green card or the U.S. Citizen & Immigration Service determines that you have abandoned your green card and takes it away from you, you will need to follow the nonresident alien requirements for filing a Form 1040-NR, U.S. Nonresident Alien Income Tax Return.

You are a long-term resident for U.S. federal income tax purposes if you were a lawful permanent resident of the United States (green card holder) in at least 8 of the last 15 tax years ending with the year your residency ends. In determining if you meet the 8-year requirement, do not count any year that you are treated as a resident of a foreign country under a tax treaty and do not waive treaty benefits.

If you are a long-term resident who has surrendered your green card, you may be subject to the expatriation tax. In general, the expatriation tax provisions apply to U.S. citizens who have renounced their citizenship and long-term residents who have ended their residency. The rules that apply are based on the dates of expatriation.

U.S. citizens and resident aliens living outside the United States generally are allowed the same deductions as citizens and residents living in the United States. If you paid or accrued foreign taxes to a foreign country on foreign source income and are subject to U.S. tax on the same income, you may be able to take either a foreign tax credit on foreign income taxes or an itemized deduction for eligible foreign taxes. However, if you take the foreign earned income exclusion your foreign tax credit or deduction will be reduced.

Yes, since the foreign earned income exclusion is voluntary, you must file a tax return to claim the foreign earned income exclusion. It does not matter if your foreign earnings are below the foreign earned income exclusion threshold. There are specific requirements that you must satisfy to be eligible to claim the foreign earned income exclusion.

You will need to contact the Social Security Administration, as the IRS does not issue SSNs. Use Form SS-5-FS, Application For A Social Security Card, which may be obtained from and filed with the Social Security Administration.