What does Box 21 mean on the K-1 for partnerships?
Box 21 reports foreign taxes paid or accrued. These taxes reduce a partner's basis and are limited to the basis.
See your Schedule K-3, Part III, Section 4 for more information to claim the Foreign Tax Credit. If your partnership didn't provide a Schedule K-3 to partners and you need the information from a Schedule K-3 to claim the Foreign Tax Credit, you can request one from your partnership.