Cannot upgrade to Catalina on MacBook 2017 with Mojave 10.14.6

You are trying to update Mojave, not upgrade it. See How to upgrade to macOS Catalina.

ianlivechange wrote:

So I'm still not in? It gives me the same response "your Mac is up to date". Should I download the Catalina installer? Where do I get this from?

Ian

As I wrote above, you get it from the Mac App Store.

ianlivechange wrote:

How do I upgrade to Catalina? Every time I try to upgrade it says "Your Mac is up to date"

Run this command in the Terminal then reopen System Preferences > Software Update.

sudo softwareupdate --reset-ignored

You upgrade by opening the App Store, from the Apple menu, and searching for Catalina.

Before you upgrade, make sure to have a full backup or three.

Have you opened About This Mac from the Apple menu to see what version of macOS is actually installed? Did you download the Catalina installer from the App Store or did you try using Software Update?