Would like to know how Microsoft Bot Service Provision Skype bot , Need to check the underline code how microsoft bot service is using Skype API to create skype bot. Please provide the reference and source code.
The code you are asking for is not open source. Bot Framework has many pieces open source (like the SDKs, the Emulator, the WebChat control among others) but the piece you are asking is not.
I suspect you have another issue; so I would recommend either to post a new question with the specific problem or clarify this one.
If you want to learn how Skype works with BotFramework, pleas read https://dev.skype.com/bots.