How do I update macOS from Big Sur to Monterey on MacBook Pro

I want to upgrade my iOS which is not compatible with some newer software I need. When I go to Software update, it says I am up to date. I can't even find Monterey on the AppStore.

Can I upgrade to v12 with my old laptop? If so, how?

Thanks,

karkauai

[Re-Titled by Moderator]