With BuddyForms Custom Login you can force the user to log in and create a private site or network.
List of all options can be found here: Custom Login Options
Only make certain Pages and Post Types availöable for the Public
If the "Redirect logged off users to a login and create a private site or network." option is set to yes all parts of your site will get logged for unregistered users.
If you want to allow you, users, to display certain pages of your site you can use the "Public Accessible Pages" option to make certain pages accessablöe to the public. You can do the same for any custom post type if you select the post types under the "Public Accessible Post Type" option.
If you run a WooCommerce store and want to generally force login but keep the store public accessible for unregistered users so that they can buy a product or a membership or subscription you need to make sure that your shop is accessible. To do so make sure you have the My Account Page and the post type product selected like in the image.