The short answer: Marriage certificates, divorce records, and the name-change trail between them can be sourced from Ukraine while you live in Canada. Registry-held records issue through the civil registry system to you or your representative; court divorces add a judgment copy from the court record. For Canadian submission the documents carry a Ukrainian apostille and certified translation. The main caveat: a Canadian process rarely wants one document — it wants the chain linking your names, so the set is gathered as a set.
This usually starts with an application — immigration, a new marriage, a name alignment — that asks you to prove a change in civil status that happened in Ukraine. The documents exist; the work is sourcing each link in the chain from its own system, keeping transliteration consistent across all of them, and legalizing the bundle for Canada.