Trouble updating to mac OS Catalina

You could give this a try.

https://apps.apple.com/us/app/macos-catalina/id1466841314?l=en-us&mt=12

See if the solution found by the user works for you: Can't Download Catalina Via Software … - Apple Community

You can try to perform a clean install of macOS catalina on your MacBook. Doing this will help you cut down bugs of this new version. If you do not know how to do it, let me know.

Hi Dear Penny here I trying to update Mac OS Catalina on my MacnookAir On screen said 10:15 - 8: 18 GB I understand that mean my MacBook doesn't have enough space for Catelina Right

Thanks

Penny