I have done this multiple times when I need to create a duplicate VM having same configuration set as before.
The steps are quite simple and pretty straight forward:
Create a Snapshot of your OsDisk.
Once you have got your snapshot created, create a disk using this snapshot.
Once you have got your Disk created from the snapshot, the last step is to create a VM using this snapshot.
You need to fill in the options for the VM as usual and click “Create”.
This is how you can duplicate your VM and can create multiple VMs with the same configuration as the base.
I hope it helps!