You could just attribute that volume to a family member or colleague to use so that you don’t mix up your files, but a popular scenario would be to use this volume to install an alternate version of the Mac operating system on. Now you can click Add and your new Volume will be added to your Mac.Remember you will actually need to have enough space available on your Mac to allocate this way (which is why we started by advising you to delete things from your Mac!) If you want to, click on Size Option and fill in the Reserve (minimum) and Quota (maximum) options. You can now choose to set a storage limit for this volume, but you don’t have to.Give your new volume a name, we called ours Test, but you might want to call it Mojave or Beta, if you were planning to install that version of the OS on that volume.Now all you need to do is click on the + button above Volume in the menu to create your new Volume.Select the Home volume, and double check that it is an APFS Volume (it needs to be for this to work).This will make sure you can see the volumes within your disk. Click the drop down menu beside the View button in the toolbar and choose Show All Devices.That space can be made available to all the different volumes at any time, rather than being assigned to them when they are formed, as is the case with a partition. APFS has a number of advantages over HFS+ one is Space Sharing, which makes it possible for the available space to be shared between the different volumes on your disk. This is thanks to the new Apple File System (APFS) which replaced the old HFS+.

If you are running High Sierra on a Mac with a Flash drive, or Mojave on any Mac then you don’t need to create a partition at all, you only need to create a new volume. (This is a little confusing, because essentially a volume and a partition are the same thing, but newer versions of the macOS handle things differently enabling users to create a volume and use it in the same way as a partition would have been used, but without any of the complications of having to wipe the Mac and start from scratch). The most important point is to establish whether you will even need to create a partition, or, if you can just create a volume on your Mac. There are a few factors that will determine how you go about your project.

How to partition disk mac