how many mails do HK have?and what are they?

Are you trying to say how many email service providers do Hong Kong have?

Techniacally, all email service provider are international, since wherever you can access internet then you can access your email. Although some are more popular than the others, like Gmail and Yahoo. Those name you have mentioned could refer as Webmail.


From wikipedia
Web-based email or webmail is a term referring to an e-mail service intended to be primarily accessed via a web browser, as opposed to through an application such as Mozilla's Thunderbird, Apple's Mail or Microsoft Outlook.