One can also use the Disks application built-in to Zorin OS.
Open Disks.
Select the drive you want to create a clone of.
Click the '3-vertical-dots' button at upper-right.
Select "Create Disk Image".
Tell it where to save it, and it'll create a .IMG file which is an exact duplicate of that entire drive.
You can then use 7z to compress that, if you like, to save drive space if you're using that .IMG file as a backup... it's best if you zero the free drive space before taking a .IMG file, as zeros compress really well (in effect, you're creating what's known as a "sparse file" backup of that drive). I compressed three .IMG files of three identical 500 GB drives into a single 7.6 GB .7z file because the free space on each drive was zero'd.
You can then use Disks to populate another drive with that .IMG file by selecting the drive you want to work with, clicking that '3-vertical-dots' button and selecting "Restore Disk Image", selecting the .IMG file you'd previously created, and letting it run. It'll be an exact duplicate of the original disk.
This can be a problem in some circumstances... the drives will have the same UUIDs and PartUUIDs... so if you're going to use both the original and the cloned drive in the same system, you should change the UUIDs and PartUUIDs of the clone.