The short answer: You can issue a fully valid power of attorney for use in Ukraine without leaving Canada. The two working routes are: sign before a Canadian notary, get an apostille (Canada has been a Hague Apostille party since January 11, 2024), and add a certified Ukrainian translation — or sign directly at a Ukrainian consulate, which certifies the document itself. The main caveat: Ukrainian notaries read powers of attorney literally, so the text must name the specific acts, objects, and person — a vague 'universal' text gets refused at the exact moment you need it.
In practice, the power of attorney is the single most-used instrument for Ukrainians abroad: it lets someone you trust act in your name for property, banking, registry filings, or court representation. The wording is the product — a well-built text lists exactly what the holder may do, for which property or company, with which sub-delegation rights, and until when.