I think having a privacy policy statement is becoming a legal requirement in many countries, so it seems that one will be compelled by Google, at some point, if not already, hence your question, to have one attached to all Apps that harvest information from a third party user.
But, you said "...I should mark in the privacy policy form?" . . . . if that means what should a privacy policy contain ... without being "funny about it" there must be pro-forma policies one can find on Google search. Most of the one's I have seen are "boiler-plate" versions that cover general protections of personal data, promises not to share data with any other party (sort of thing Facebook wants to do between Instagram and WhatsApp and FB - and why they recently asked people to agree their "free-use" of data they harvest off you - and have done for years) etc etc.
SA has the Protection of Personal Information Act which governs what data entities / organisations can store, when they have to delete this information, what of these data are accessible and by whom - - - etc etc etc.. And, so, what you sell via Play Store to a person living here must have relevant declarations.
Such things would be in these Privacy policies.
Don't know if that answers anything in your question . . . but anyway. . . . .