As per CRA:
Filing electronically
Keep all your documents in case the CRA asks to see them at a later date.
Filing a paper return
Attach your completed Form T2209, Federal Foreign Tax Credits, and documents such as official receipts, that show the foreign taxes you paid and a note showing your calculations. If you paid taxes to the United States, attach your W-2 information slip, U.S.1040 return, U.S tax account transcript, and any other supporting documents that apply.
If any of your documents are in a foreign language, the CRA needs a copy of the original documents written in the foreign language with an acceptable English or French translation.
To be acceptable, the signatory’s name has to be printed, in the Latin alphabet, and the translation has to meet one of the following conditions:
- be certified by an official with the authority to administer an oath or solemn declaration (commissioner of oaths, notary public, or lawyer) unless it was done by a translator who is a member in good standing of one of the provincial or territorial organizations of translators and interpreters of Canada
- have the seal and signature of an official from the foreign country’s embassy, high commission, or consulate confirming it is a true translation
- have the seal and signature of the Chartered Professional Accountant (CPA), Chartered Accountant (CA), Certified Management Accountant (CMA), or Certified General Accountant (CGA) confirming it is a true translation
- have a written statement indicating the profession and the signature of a teacher, professor, or a religious leader confirming it is a true translation