The websites which do not change their content or the websites you visit and on each visit their all pages content number of pages stays same is called static websites.
As you know what is a website? Website is actually a page some websites are made with number of web pages and those pages contain information about purpose of website. Read more what is a website?
In static websites each page of your website have its own file in your server like about us page will must have file in your server name maybe /about-us.html or /about.html or anything else. That file contain all data of your about page including logo, header, navigation, content, sidebar, footer etc which will not change anything unless you edit that file and change information this is static website. Like if your website has 10 pages all pages have same navigation and header. If you need to change anything even a spelling mistake in header or in navigation you will need to edit all 10 files of each web page in your website. So static websites get information from files not from database. Still websites which do not change their data regularly and need you to replace each file for each page update even if all pages have same design layout using same stylesheet will repeat on each page file.