corkg and pcgeek11 are quite right. A true clone of an original drive contains absolutely everything from it, arranged properly on the copy unit. So, assuming the original drive was a bootable drive, the clone also will be.
As an example, a short while ago I proved this all for my system. I have two internal HDD's - one to boot, another with only data storage. I have one larger HDD mounted in an external enclosure, and all three drives are by the same maker. So I downloaded the free disk utility package from that maker and installed it on the C: drive. I wiped the external drive unit clean, then used the cloner utility to clone the C: drive to a new Partition on the external drive, adjusting its size two accommodate all the stuff from C: without using up too much empty space. Then I ran the cloner a second time and cloned the D: drive, making a new second Partition on the external unit to accept that. At that point on one external HDD unit I had two clones, each in its own Partition. One was the clone of the bootable C: drive, and the other the clone of the D: drive.
That way I had complete backup copies of both drives. Under "normal" conditions I could access each of the "drives" on the external unit and copy, alter or open any file on them. But - here's the final test - what about not normal conditions after my C: drive failed? So I shut down the system, disconnected both internal drives, and moved the third HDD unit from the external case into my main case, connecting it as the only HDD unit in the system. I booted up and it did exactly as I wanted - the system found the bootable clone image in the first Partition of that HDD and booted from there with no trouble. When it finished, both my C: drive and my D: drive were present and usable. The system really did not care where they were located. The only difference from "normal" was that each of those versions of my two "drives" were slightly smaller than the originals because I had made the clones that way, with less empty space on each "drive". Un-doing all that put my original two internal drives back into play, and my third drive containing the clones back into its external case.
Bottom line: as anticipated and designed, the clone copy was fully able to substitute for the original even when the original was not even present in the system.