hi

I have Question about can we use Public certificate for Server side [MP - DP - SUP], and what about clients will use Internal Certificate?

This for Scenario of Internet based c

It doesn't matter were the certificate comes from as long as it's a valid certificate. For the clients I would go for internal certificates, but that's from a cost perspective and not from a technical perspective. Technically speaking it doesn't matter were the certificate comes from.

Just to reinforce Peter's statements, as long as the certificates meet the requirements defined at https://technet.microsoft.com/en-us/library/gg699362.aspx then ConfigMgr will use them. Do note however that ConfigMgr doesn't really use the certs on site systems though, IIS does (that's kind of splitting hairs here though).