If she did not receive a W-2, she should enter her income as foreign earned income.
She may be able to exclude part of her foreign earned income if she was not in the US for more than 35 days in ANY 12 month period. So if she only had 35 US days from March 2018 to March 2019, she could tax a partial exclusion for 2018. The full exclusion for 2018 is $103,900.
If she does not qualify for the foreign earned income exclusion, the software will still keep track of her foreign wages not reported on a W-2. Then she should go to the foreign tax credit (I'll give instructions below) section of TurboTax to enter her foreign wages and foreign tax.
To enter her foreign income, type in foreign income in the search box at the top of the screen. Click the Jump to foreign income link. This is where you need to enter her foreign wages. https://www.irs.gov/individuals/international-taxpayers/yearly-average-currency-exchange-rates
Then is she does not qualify for the foreign earned income exclusion, then go to the foreign tax credit section to get a credit to help offset double taxation.
To enter her foreign tax credit, type foreign tax credit in the search box at the top of the screen. Click the Jump to foreign tax credit. Respond to the screens and continue until you see the types of income. Wages are considered general category income. Enter her country, her wages for Korea and her income tax paid (in the other tax . If she did not pay any Korean taxes in 2018 but will only pay them in 2019, then you need to input that her taxes are on the accrued basis. If she paid her foreign taxes in 2018, then she would be on the paid basis for foreign tax.
