Perform the following in the Azure Console:

1. Go to Storage Accounts
2. For each storage account, go to Encryption
3. Set Storage service encryption to Enabled

Default Values:
By default, Storage service encryption is set to Disabled for Blob service.

References:

1. https://docs.microsoft.com/en-us/azure/storage/storage-security-guide#encryption-at-rest
2. https://docs.microsoft.com/en-in/azure/storage/blobs/storage-java-how-to-use-blob-storage#overview
3. https://docs.microsoft.com/en-us/cli/azure/storage/account?view=azure-cli-latest#az_storage_account_list
4. https://docs.microsoft.com/en-us/cli/azure/storage/account?view=azure-cli-latest#az_storage_account_update