Each country affixes the Hague Apostille to its own documents
The rule is that each country affixes the Apostille to its own documents: for example, for a document issued in the UK the Apostille cannot be affixed in Romania, just as for a document issued in Romania the Apostille cannot be affixed in the UK.
In other words, each country member the Hague Convention (5 october 1961) is responsible for issuing Apostille for documents originating within its jurisdiction.
So, if you have a document from abroad (from a country member of the Hague Convention and with which Romania has not concluded an Apostille exemption treaty) to be used in Romania, before coming to Romania with that document, check with the Romanian institution (civil registry office, etc.) where you will submit the document if they require the Hague Apostille and obtain the Hague Apostille in the country where the document was issued. In other words, do not bring the document to Romania without the Apostille, because if in Romania you are asked for the Apostille on that document, you will have to send it back to the country where it was issued to have the Apostille affixed.