Here’s how you can selectively enable or disable Jetpack features on self-hosted WordPress sites. This way you can activate only those features that you wish to use.
Show or Exclude Posts from Certain Categories on Homepage
Add any of these code snippets to your active theme’s functions.php file in order to include or exclude one or more categories from the loop on your home page.
WordPress: Enable Email Address Login & Change Login Page Text
Drop this code snippet into your theme’s functions.php file to enable user login with email address, and also change login page text to inform about this functionality.