The U.S. tax for a US citizen or resident alien (who lives abroad) is generally the same whether you are in the United States or abroad. Your worldwide income is subject to US income tax, regardless of where you reside.

American Citizen or Green Card Holders Living Abroad: Notes To Clarify

If you are an American taxpayers or US citizen living abroad or Green Card holder or have any US source income, you are required to file the US tax and report your worldwide income. You may be eligible to claim Foreign Income Exclusion or get Foreign Tax credits to offset the taxable income and might not have to pay any or very less US tax. For US citizens and residents who are living abroad, can easily submit American tax with us.

Tax Deadline for Expats:

Taxpayers residing in the United States are required to file their US taxes by April 15th (Note: for 2018 tax returns, the due date is April 17th,). However, if you are taxpayers Americans living abroad or out of the country on the filing date the rules for tax filing dealine are different.

Please note any taxes due are required to be paid by April 17th deadline irrespective of being an Expat.
Most expats qualify for an automatic two-month filing extension. So 2018 tax returns due on June 15th (Note 2018 returns are due June 17th)

If you are unable to file your return by the automatic 2-month extension date, you can request an additional extension to October 15 by filing Form 4868 before the automatic 2-month extension date. However, any tax due payments made after June 15 will be subject to both interest charges and failure to pay penalties.

Paper Filing your returns :

Just like the time associated for filing American tax for expats is different, you need to be aware of the address where you can mail your Federal returns. File your return using the appropriate address for your circumstances:

Requesting a refund, or no check or money order enclosed:

Department of the Treasury
Internal Revenue Service
Austin, TX 73301-0215

Enclosing a check or money order:

Internal Revenue Service
P.O. Box 1303
Charlotte, NC 28201-1303

A clear idea on Electronic Filing or e-file:

It is mandatory for people to learn more about electronic filing or e-file while considering filing US taxes even when living abroad. Read also: How to file us income tax return online through IRS

• Taxpayers with the AGI or the Adjusted Gross Income within a specified threshold can file for their tax return electronically for free by e filing their returns.
• Taxpayers associated with AGI greater than any specified threshold can often use Free File Fillable Form or the e-file by purchasing commercial software.
• There are limited numbers of companies, which offer software, which can be used for accommodating foreign addresses.

Just for determining which one works best for you, get some help in choosing a software provider.

More about Free File:

To save hard earned money while filing for us tax for us citizens living abroad, you need to be aware of what exactly “Free File” is. Right now, Free File is closed for the season and you can check back in January to file 2018 tax return. In the Free File, you can prepare and file federal individual income tax return for free with the help of tax preparation and filing software. Free File will cover all kinds of hard work on your behalf with brand-name software or for the Free File Fillable Forms.

For income below $66,000, the Free File software can file taxes for free. The software is easy to use, making it simpler for the masses. Furthermore, you will receive Free State Return Options too.