It should work with a caveat that MacOS/OS X is an experimental and unsupported feature of VirtualBox.
3.1.1. Mac OS X Guests
Oracle VM VirtualBox enables you to install and execute unmodified versions of Mac OS X guests on supported host hardware. Note that this feature is experimental and thus unsupported.
Oracle VM VirtualBox is the first product to provide the modern PC architecture expected by OS X without requiring any of the modifications used by competing virtualization solutions. For example, some competing solutions perform modifications to the Mac OS X install DVDs, such as a different boot loader and replaced files.
Be aware of the following important issues before you attempt to install a Mac OS X guest:
Mac OS X is commercial, licensed software and contains both license
and technical restrictions that limit its use to certain hardware and
usage scenarios. You must understand and comply with these
restrictions.
In particular, Apple prohibits the installation of most versions of
Mac OS X on non-Apple hardware.
These license restrictions are also enforced on a technical level.
Mac OS X verifies that it is running on Apple hardware. Most DVDs
that accompany Apple hardware check for the exact model. These
restrictions are not circumvented by Oracle VM VirtualBox and
continue to apply.
Only CPUs that are known and tested by Apple are supported. As a
result, if your Intel CPU is newer than the Mac OS X build, or if you
have a non-Intel CPU, you will likely encounter a panic during bootup
with an "Unsupported CPU" exception.
Ensure that you use the Mac OS X DVD that comes with your Apple
hardware.
The Mac OS X installer expects the hard disk to be partitioned. So,
the installer will not offer a partition selection to you. Before you
can install the software successfully, start the Disk Utility from
the Tools menu and partition the hard disk. Close the Disk Utility
and proceed with the installation.
In addition, Mac OS X support in Oracle VM VirtualBox is an
experimental feature. See Chapter 14, Known Limitations.
Known Limitations
On Mac OS X hosts, the following features are not yet implemented:
Numlock emulation
CPU frequency metric
Memory ballooning
Mac OS X guests:
Mac OS X guests can only run on a certain host hardware. For details about license and host hardware limitations. See Section 3.1.1, “Mac OS X Guests” and check the Apple software license conditions.
Oracle VM VirtualBox does not provide Guest Additions for Mac OS X at this time.
The graphics resolution currently defaults to 1024x768 as Mac OS X falls back to the built-in EFI display support. See Section 3.14.1, “Video Modes in EFI” for more information on how to change EFI video modes.
Mac OS X guests only work with one CPU assigned to the VM. Support for SMP will be provided in a future release.
Depending on your system and version of Mac OS X, you might experience guest hangs after some time. This can be fixed by turning off energy saving. Set timeout to "Never" in the system preferences.
By default, the Oracle VM VirtualBox EFI enables debug output of the Mac OS X kernel to help you diagnose boot problems. Note that there is a lot of output and not all errors are fatal. They would also show when using a physical Apple Macintosh computer. You can turn off these messages by using the following command:
VBoxManage setextradata "VM name" "VBoxInternal2/EfiBootArgs" " "
To revert to the previous behavior, use the following command:
VBoxManage setextradata "VM name" "VBoxInternal2/EfiBootArgs" ""
It is currently not possible to start a Mac OS X guest in safe mode by specifying "-x" option in "VBoxInternal2/EfiBootArgs" extradata.
Sources:
https://www.virtualbox.org/manual/UserManual.html#intro-macosxguests
https://www.virtualbox.org/manual/UserManual.html#KnownIssues
While not free, VMware Fusion 11.5 does officially support MacOS Mojave and High Sierra.
https://www.vmware.com/products/fusion/faqs.html#virtual-machines
https://www.vmware.com/go/fusionoperatingsystems
Considering it's a mission critical app, you may want to consider Fusion instead.