Hi @A .H ,
yes. If a VM in Azure is stopped/deallocated you will be billed/charged for the disk(s) of the VM based on the disk's SKU.
This is because the disk(s) still exists and is consuming resources in Azure datacenter.
(If the reply was helpful please don't forget to upvote and/or accept as answer, thank you)
Regards
Andreas Baumgarten