Unfortunately Breezi does not currently provide the ability to password protect pages, if you want to make certain pages only accessible by people who you give a password to.
However, you are able to hide any page from search engines when you’re logged in by clicking “Pages” on the bottom toolbar, and then clicking the pencil icon on the page you’d like to hide, to access the “Page Settings”. There you’ll want to click “SEO Settings” and then at the bottom click the “Hide from Search Engines” checkbox. Click “Update!” and search engines will no longer crawl that page. Taking this idea of “hiding” pages a step further, you can always create pages on your site and not link to them, so as to make them difficult to access without the exact URL to the page.