If you are a US citizen or green card holder, you must file a US resident return declaring your worldwide income for the calendar year 2017. Assuming you worked in the UK for the latter part of the tax year, you will need to include any income you received in the UK, using currency exchange rates into USD. If you paid tax in the UK on that income, you would include it as a foreign tax credit to help offset US tax on that same income.
Click on Federal tab at left of screen
Click on "Wages and Income" at the top of your
screen
Scroll down to last option "Less Common
Income"
Click on start next to "Foreign Earned Income
Exclusion"
For more information on the foreign earned income
exclusion please see the following link
Tax Guide for US Citizens Abroad
