I do not know exactly about annotations and highlights, I do not use them. I use only scribles.
All three are stored in SQL database, not in pdf. It is possible to create a new pdf which includes scribles or annotations & highlights. Maybe even all three. So, before you may use scribles/annotations/highlights outside M92, you must create a new pdf which incorporates them.
Scribles are visible in different pdf readers on PC, but are not printed. To be able to print them you have to flatten the pdf. (Maybe that some pdf reader is able to print scribles without flattening, but I am not aware of any - for Win)