Apostille or legalization procedure is required for all official Ukrainian documents designed to be used abroad. It refers to documents issued by civil registry offices in Ukraine, like birth certificates, marriage certificates, divorce certificates, diplomas with supplements and school certificates with supplements, notarized powers of attorneys, police clearance certificates, medical certificates, etc.
Apostille stamp is obligatory for countries being parties to Hague Convention, like the USA, the UK, Italy, Spain, France, Switzerland, Israel, Australia, Japan, etc. In its turn, if you are to submit documents from Ukraine in Canada, the UAE, China, Vietnam, Jordan, Kuwait, Egypt, etc., documents must bear legalization stamp.
In case you don’t know what steps to take you’d better ask a translation agency in Ukraine to prepare all the package for use in either a Hague Convention country or some other country not being a signatory of the mentioned Convention.