Most website builders limit you to choosing from one of the same boring templates already being used by hundreds, if not thousands of other websites. Then their idea of customization is allowing you to swap out text and align it left, center, and right. Those type of limitations don't give you the flexibility and control required to succeed online.
Good question. Depending on the builder that you are using you will have a couple of options, these being termed password protected pages or members only area. I’d look to see if the website builder which your site is created on incorporates password protected pages, as this will allow you to have a block to your site until a password is entered. Wix, Weebly Squarespace, Site 123 all allow for this to name but a few.
WordPress vs. Joomla/Drupal: Drupal is a very powerful platform that is popular with web developers and experienced coders, but it comes with a very steep learning curve that makes it a bad choice for beginners. Joomla is similar to WordPress and works great for online stores, but you’ll need at least a little bit of technical coding to make it work the way you want.