If you are a resident alien, the rules for filing income, estate, and gift tax returns and paying estimated tax are generally the same whether you are in the United States or abroad. Your worldwide income is subject to U.S. income tax the same way as an U.S. citizen. You are a resident alien of the United States for tax purposes if you meet either the green card test or the substantial present test for the calendar year.
In some cases aliens are allowed to make elections which override the green card test and the substantial present test. For example, if, at the end of the tax year, you are a resident alien and your spouse is a nonresident alien, you can choose to treat the nonresident alien spouse as a U.S. resident alien and file Form 1040 using the filing status Married filing jointly.
Tax Treatment of Resident Alien
If you are a U.S. resident alien, you can use the same filing statuses available to U.S. citizens. You can claim the same deductions allowed to U.S. citizens if you are a resident alien for the entire tax year. You can claim personal exemptions and exemptions for dependents according the dependency rules for U.S. citizens. You can claim the same itemized deduction as U.S. citizens or you can claim the standard deduction for your particular filing status. You can claim the same tax credits using the same rules that apply to U.S. citizens. You use the same forms and mailing addresses as U.S. citizens.
See Alien Taxation – Certain Essential Concepts for a summary of some rules that apply to resident and nonresident aliens.
Electronic Filing (e-file)
Taxpayers with an AGI (Adjusted Gross Income) within a specified threshold can electronically file their tax return for free using Free File. Taxpayers with an AGI greater than the specified threshold can either use the Free File Fillable Forms or e-file by purchasing commercial software. A limited number of companies provide software that can accommodate foreign addresses. To determine which will work best for you, get help choosing a software provider.