You can make a mirror of a website with software which was created for this type of job and you will be able to copy only the HTML version of the website because in cases where the website is built using PHP technology you will download what is processed, and the PHP files will remain in their original location which is unavailable for downloading because of the server-side restriction.
Basically, you can create mirrors of all websites but you will have the results not from the source of the website.
From my personal experience, I can recommend software like HTTrack because it has different methods of copying and mirroring. All you need to do is to enter the URL of the website, select the depth level and start the process. Please be aware that the process could take a long time based on the complexity of the website you want to copy.