A wide range of Golden Age comics and historical comics with public-sharing permissions are available, covering genres such as superheroes, science fiction, adventure, and horror.
Public Domain Comic Digital Archive
Click the "Visit Site" button on this page to open the official Comic Book Plus website, then follow its on-screen instructions.
Comic Book Plus is accessed online through your browser, so there is usually no local installation. Refer to its official site for details.
You can browse comparable reading sites under the e-books category on this site and pick the one that fits you.