Information from the website of masterkey.ua, the operator of the Art Zvit software, which Ukrainian businesses use to file tax reports electronically:
To register a personal data database (PDD) electronically with the State Service for Personal Data Protection, you can use the digital signature from the “Otchetnost” (“Reporting”) package.
[The page then points to the State Service’s own notice on electronic registration at zpd.gov.ua, a step-by-step instruction at https://www.masterkey.ua/page2721.html, and the Masterkey forum for questions.]
In other words, the Masterkey digital signature (the Art Zvit software) will do for filing an application to register a personal data database.
Still, lawyers Viktor Ageyev and Alexander Slavskiy advise at their seminars not to rush with filing that application.