wordpress 4.6 have default functionality that send mail subscriber

No, the name of the Subscriber role is a bit of a mislead. In the old days, the developers decided to create a user role that could only edit its profile but could be extended by plugins.

They figured that subscription plugins would love to make use of this, so they named the role Subscriber. Back then, a few subscription plugins did use WordPress’s users system, but today only one does, and the rest manage their own users system.

To answer your question though, WordPress does not have any subscription functionality built in, you will need to use a plugin for that, like https://wordpress.org/plugins/jetpack/ or https://wordpress.org/plugins/wysija-newsletters/