What do I need to do the same service as skype?

I want to do the same service as skype.
① Mutual call with the same application.
② A function to call a general telephone.
③ I also want to sell phone numbers.
Do you have a separate telephone function?

Please tell me what theme to buy.

I don’t understand.
Can I buy voIP at Theme forest?
Is wordpress limited to templates?

The following theme “Tinno” allows mutual calls.
Is “Biz wall” a template?
how is it?