I have MacOS Sierra on my computer, how can I upgrade to Mojave?

If you have issue— verify you are using the Safari browser to download the macOS

you can try

macOS 10.14 Mojave - Technical Specifications:

https://support.apple.com/kb/SP777

Upgrade to macOS Mojave - Official Apple Support

https://support.apple.com/macos/mojave

https://itunes.apple.com/us/app/macos-mojave/id1398502828?mt=12

MacBook (Early 2015 or newer)

MacBook Air (Mid 2012 or newer)

MacBook Pro (Mid 2012 or newer)

Mac mini (Late 2012 or newer)

iMac (Late 2012 or newer)

iMac Pro (2017)

Mac Pro (Late 2013; Mid 2010 and Mid 2012 models with recommended Metal-capable graphics cards)

Don't use FireFox for this link…

https://itunes.apple.com/us/app/macos-mojave/id1398502828?mt=12

If you get a corrupted message...

Naw, not damaged, it's just that you have an old copy already in Applications, Trash the Install MacsOS Mojave.app in Applications then a new copy can be downloaded.

I was able to download it from https://apps.apple.com/us/app/macos-mojave/id1398502828?ls=1&mt=12 there, just be wary that you use either chrome or safari, or when using firefox select to open the link with AppStore app and not with iTunes.

That error can mean that you already have an older version of the installer on your hard drive. Look in your Applicaitons folder and, if you find it, delete it and try again.