The Custom Attribute feature allows users to configure custom attribute mapping in Salesforce for desired objects. When files are uploaded from Salesforce, the values corresponding to specified fields in this custom attribute mapping will be sent to Azure Blob Storage to set the 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