Apple's new macOS Mojave was just announced June 4, 2018, and will be officially launching in the Fall. Currently, it is in Beta, and not yet a final public release.
Intuit does NOT support running any of its software on Beta versions of any operating system. We won't take steps to prevent customers from installing, but please know that some features may not run correctly. QuickBooks is always designed and built to run on the final public release of the macOS version that is available at the time of development.
If you encounter issues running QuickBooks for Mac on macOS Mojave while it is in Beta, please make sure the customer reports it to Apple.