The short answer: Your Canadian document can be made valid for use in Ukraine while you stay in Canada. Canada has been part of the Hague Apostille Convention since 11 January 2024, so the chain is: apostille in Canada — Global Affairs Canada (JLAC) for federal documents, a provincial authority such as Ontario's Official Documents Services for provincial ones — then a certified translation into Ukrainian on the Ukrainian side. The main caveat: the apostille authority depends on which Canadian level issued the document, and sending it to the wrong one costs weeks.
This usually means someone in Ukraine — a school, a registry office, a court, a notary — asked for proof of a Canadian fact: a birth, a marriage, a name, a status. Your job is to send the document in the form a Ukrainian institution can legally accept, and the two reliable variables are the correct apostille authority and a Ukrainian translation done to notarial standard.