I don't know about Windows, but on macOS you can. If you wanted to try yourself you could use SingleFile to export a webpage as a .html zip file which you could then just 'open' into the web browser.
For a web app, you might have to unzip it and launch the .html inside. CyberChef for example does offer a downloadable copy of its web app instructing you do just that.
For a web app, you might have to unzip it and launch the .html inside. CyberChef for example does offer a downloadable copy of its web app instructing you do just that.
[1]: https://gchq.github.io/CyberChef/