The details & additional links with information are here:
• How to get old versions of macOS - Apple Support
https://support.apple.com/en-us/HT211683
Newer details also are within this page/links.
(..If your usual applications need 32-bit drivers, you
may find newer 64-bit apps. Or upgrade to Mojave
10.14.6 instead of later '64-bit catalina or big sur'..)
• Go G4 - makes it easy to upgrade for the future.
https://www.stclairsoft.com/Go64/index.html
"A fast, free way to get a comprehensive look at your 64-bit app
compatibility ... avoid surprises before installing macOS Catalina."
Good luck & happy computing!
🌞🌿⛵️🌤🎣🤖🏕🐝⛄️🌻