Welcome to Upgrade Your Mac!
If you're asking why the website looks so bad, it's so that out-of-date
macs have no problem rendering this website.
Upgrade old macs to a better OS X (DMGs)
OS X Sierra DMG Download (10.12)
OS X El Capitan DMG Download (10.11)
OS X Yosemite DMG Download (10.10)
Download Catalina Patcher (for the full installer)
Catalina Patcher Download (use to download full installer)
If your mac can't upgrade no later than Catalina... (10.15)
Install OpenCore Legacy Patcher (2.3.2)