Disclaimer: This is the forum for ko-kr locale. However, I will support you in English since the thread is in English, If you need support in your local language, please let me know.
Hello 준 정,
Welcome to Microsoft Q&A forum.
Windows 8 has been out of support since 2023, and there will be no further updates to it.
The installation files as I checked have been removed from the Microsoft Store, and all is left is some last updates for the edition. In this case, if you want to download it, you can try to find it on the Internet Archive (safer choice) or download the .iso file from another website.
Please note that download the product from a third-party website might contains risks, so please check carefully before downloading anything. Also, Windows 8 is no longer received security updates or bug fixes, make it much more vulnerable to attacks. So if you have the chance, I'd suggest you upgrade to the latest version. Thank you for your understanding.