The requirements for Hong Kong visit visa are:
Application for Entry for Visit/Transit in Hong Kong (ID 1003A)

The applicant's recent photograph (affixed on page 1 of the application form ID 1003A)

Photocopy of the applicant's travel document

Photocopy of proof of the applicant's financial standing, e.g. bank statements, savings accounts passbooks, tax receipts, etc. and proof of employment (if any), e.g. company leave letter, salary slips, etc.

Photocopy of proof of transportation arrangement, e.g. flight itinerary

Photocopy of proof of the proposed leisure visit to Hong Kong, e.g. receipt of joining a package tour to Hong Kong, itinerary, etc. (for leisure visit only)

It takes 4 working days for visa processing, however, if the China embassy/consulate needs the approval for your application from Immigration Department of HKSAR, it takes 1 month.

I heard that Hong Kong and Ukraine have already signed a bilateral visa cancellation arrangement, however I am not sure when it will actually be in effect.