Your company does not need to send any information to the IRS.
As a US citizen, you are responsible for reporting your worldwide income on your US tax return. You are required to file taxes on foreign income even if you pay taxes in the host countries. There are a couple of tax breaks you may be able to take advantage of, but you must file a tax return and you must include all of your income.
You will report this income in the Foreign Income section of Turbo Tax. You can select " a statement from my foreign employer (could be cash)" as the source of your income.
Tor report Foreign Income:
Select Federal Taxes
Select Wages and Income
Scroll down and select Show More at Less Common Income
Select Start at Foreign Earned Income and Exclusion
Tax breaks you may qualify for include:
Foreign Earned Income Exclusion - An American living and working abroad can exclude foreign-earned income up to $100,800 as of 2015 from U.S. taxation. To qualify, you must have lived outside the United States for 330 days in 12 consecutive months.
Foreign tax credit - You are allowed a credit for taxes paid to a foreign country. It is calculated by subtracting the lower tax rates (US or Foreign rate) from the higher. You pay only the higher of the two tax rates, split between the two countries.
See https://turbotax.intuit.com/tax-tools/tax-tips/General-Tax-Tips/Filing-Taxes-While-Overseas/INF19130.html and https://www.irs.gov/Individuals/International-Taxpayers/U.S.-Citizens-and-Resident-Aliens-Abroad for more information.
For UK earnings would I need to submit documents to the IRS and if so what documents?
Thanks.