Archiving web pages correctly is not always easy. For this reason, we can only briefly discuss the most important problems here.
First of all, you should be aware that we generally cannot simply save web pages simply save them as a file on the hard disk, as almost every web page today consists of far more than one file or is even built up dynamically (content comes from a database).
There are currently (in 2025) two main options for archiving web pages. Firstly, there is the SingleFile add-on for many browsers. And there is also the tool capt2pdf
(for Linux only).
However, the option to print websites directly from the browser is not really recommended. This usually works rather poorly (even with current browsers).