If you paid or accrued foreign taxes to a foreign country or U.S. possession and are subject to U.S. tax on the same income, you may be able to take either a credit or an itemized deduction for those taxes.

You can take the foreign tax as a deduction or claim as a credit to reduce your U.S. taxable income/tax liability. In most cases, it is to your advantage to take foreign income taxes as a tax credit.

You can claim a credit only if your foreign taxes are qualified:

1.	The tax must be imposed on you: you can claim a credit only for foreign taxes that are imposed on you by a foreign country or U.S. possession.
2.	You must have paid or accrued the tax: You could claim a credit only if you paid or accrued the foreign tax to a foreign country or U.S. possession. If you file a joint return, you can claim the credit based on the total of any foreign income tax paid or accrued by you and your spouse.
3.	Your qualified foreign tax is only the legal and actual foreign tax liability that you paid or accrued during the year. The amount of the foreign tax that qualifies for the credit must be reduced by any refunds of foreign tax made by the government of the foreign country or the U.S. possession.
4.	Generally, only income, war profits, and excess profits taxes (collectively referred to as income taxes) qualify for the foreign tax credit. Foreign taxes on wages, dividends, interest, and royalties generally qualify for the credit.

You can file Form 1116 to compute your foreign tax credit for certain taxes paid or accrued to foreign countries or U.S. possessions.

The foreign tax credit is calculated as follows:

Step1:	Determine the qualified foreign income taxes paid or accrued for the tax year.
Step2:	Compute the foreign tax credit limitation. Your foreign tax credit cannot be more than your total U.S. tax liability multiplied by a fraction. The numerator of the fraction is your taxable income from sources outside the United States. The denominator is your total taxable income from U.S. and foreign sources.
Step3:	Determine the lesser of qualified foreign taxes paid (step 1) or the foreign tax credit limitation (step 2).

Any unused foreign tax credits can be carried back one year and then carried forward for 10 years.

[Reference]:
https://www.irs.gov/individuals/international-taxpayers/foreign-tax-credit
https://www.irs.gov/individuals/international-taxpayers/what-foreign-taxes-qualify-for-the-foreign-tax-credit
https://www.irs.gov/individuals/international-taxpayers/foreign-tax-credit-how-to-figure-the-credit