Yes, metadata (key-value pairs) attached to files in Azure Blob is synchronized with Salesforce during the file transfer process, ensuring that essential data remains intact and accessible.
Below are images with details:
Image 1 – This shows the Salesforce Org Cloud Document and Custom Attributes record details.

Image 2 – This displays how the migrated file retains its metadata.

P.S. Discover Azure Integration, the easy way to upload files from any Salesforce record to Azure. Find it on AppExchange: https://appexchange.salesforce.com/appxListingDetail?listingId=c9e71bd6-5bab-4182-a461-b82d4f971183