A website may consist of multiple pages (such as a portfolio, company website, blog) or just a single page (like a landing page, event promo page, etc). The key difference is in the settings: Style (fonts, colors) is assigned at the website level, and the domain is connected to the entire website.
So, if you’re creating multiple landing pages or articles that share the same style (fonts, colors) and are hosted on the same domain, you only need one website. However, if you want to create separate standalone pages with different styles and domains (e.g., landing pages for different clients), you will need multiple websites.