Can't Download Mojave on Macbook Pro
MacBook Pro, macOS High Sierra (10.13.4)
Please check the MacBook Pro Generation, if its old then Mojave will not work, Else Please up to date your current Mac OS first then try again.
Your computer cannot run Mojave. These computers run Mojave:
MacOS Mojave Compatibility List of Supported Macs
Apple has said that any Mac introduced in mid-2012 or later will support macOS Mojave, along with the 2010 and 2012 Mac Pro models if they have a Metal capable GPU. That’s fairly descriptive, but if you want a specific list of supported Mac hardware for macOS Mojave 10.14 then the following should be helpful to you:
As you can see from the list, basically every Mac that was introduced from mid-2012 onward supports macOS Mojave, along with a few earlier Mac Pro models. The supported hardware list for macOS 10.14 is a bit more restrictive than prior macOS system software releases, perhaps indicating that the latest software version will be more demanding on resources or simply just require particular system architecture components that are only available on more modern Macintosh hardware.
How to upgrade to macOS High Sierra
Can't Download Mojave on Macbook Pro