In this tutorial you’ll learn how to add the “Subscribe to Blog via Email” widget to your sidebar using the JetPack plugin. This widget allows readers to subscribe to your posts via email. Every time you publish a post, WordPress.com will send a notification to your subscribers.
1). In your wp-admin, install the JetPack plugin by going to Plugins > Add New. Search for, install, and activate the JetPack plugin.
2). In your wp-admin go to JetPack > Settings.
3). Activate the Subscriptions widget.
4). In your wp-admin, go to Appearance > Widgets and drag the Blog Subscriptions widget to your sidebar or footer area. Input your desired settings, and save your changes.