Документация для подтверждения налога, оплаченного в России:

Written evidence of foreign tax paid should include the following details:

the amount of foreign income or gains in the foreign currency
the foreign tax year in which the income or gains were derived
the nature and amount of foreign tax levied on the foreign income or gains
the date on which the foreign tax was paid
whether the tax paid represents an advance, instalment, or final foreign tax payment for the relevant foreign income or gains.You should provide the best available evidence to show that foreign tax has been paid. You are not entitled to a credit for foreign tax if that foreign tax has been refunded to you.

The following documents are acceptable evidence of the payment of foreign tax:

a statement from the foreign tax authority setting out the particulars that would normally be recorded on a notice of assessment, a similar official receipt, or other document evidencing payment of foreign income tax. If the foreign notice has no provision for a cash register receipt, taxpayers will be required to provide a separate receipt to indicate that the foreign tax liability has been paid. A notice of assessment which does not show that the foreign tax has been paid will not constitute sufficient proof that the tax shown on such a notice has been paid
a certificate for deduction of withholding tax issued by the person who pays the interest, dividends or any other income that is subject to a deduction of foreign tax

a distribution statement, or a similar document from a trustee of a managed fund or unit trust, stating the amount of foreign tax paid; for example, the details of foreign tax paid shown in trust distribution advices provided to beneficiaries or unit-holders will generally be sufficient to support a claim for a foreign income tax offset

payslips, payment summaries or similar documents that shows the amount of foreign tax paid will be accepted where there is no requirement in a foreign country to lodge an income tax return

a copy of the foreign income tax return, accompanied by a receipt verifying that the foreign tax, as calculated on the basis of the return, has been paid

a letter from the relevant foreign tax authority stating all taxes for that income year have been paid.