adding transactions entry to faq

Author: khdownie

articles/storage/files/storage-files-faq.md

@@ -138,9 +138,9 @@ ms.topic: conceptual
        net use <drive-letter/share-path> /delete
 
 * <a id="ad-sid-to-upn"></a>
-**Is it possible to view the userPrincipalName (UPN) of a file/directory owner in Windows Explorer instead of the security identifier (SID)?**
+**Is it possible to view the userPrincipalName (UPN) of a file/directory owner in File Explorer instead of the security identifier (SID)?**
 
-    In Windows Explorer, the SID of a file/directory owner is displayed instead of the UPN for files and directories hosted on Azure Files. However, you can use the following PowerShell command to view all items in a directory and their owner, including UPN:
+    In File Explorer, the SID of a file/directory owner is displayed instead of the UPN for files and directories hosted on Azure Files. However, you can use the following PowerShell command to view all items in a directory and their owner, including UPN:
 
     ```PowerShell
     Get-ChildItem <Path> | Get-ACL | Select Path, Owner
@@ -190,6 +190,9 @@ ms.topic: conceptual
 
 ## Billing and pricing
 
+**What are transactions in Azure Files, and how are they billed?**
+    Protocol transactions occur any time a user, application, script, or service interacts with Azure file shares (writing, reading, listing, deleting files, etc.). It's important to remember that some actions that you might perceive as a single operation might actually involve multiple transactions. For standard Azure file shares billed on a pay-as-you-go model, different types of transactions have different prices based on their impact on the file share. Transactions don't affect billing for premium file shares, which are billed using a provisioned model. For more information, see [Understanding billing](understanding-billing.md).
+
 * <a id="share-snapshot-price"></a>
 **How much do share snapshots cost?**  
     Share snapshots are incremental in nature. The base share snapshot is the share itself. All subsequent share snapshots are incremental and store only the difference from the preceding share snapshot. You're billed only for the changed content. If you have a share with 100 GiB of data but only 5 GiB has changed since your last share snapshot, the share snapshot consumes only 5 additional GiB, and you're billed for 105 GiB. For more information about transaction and standard egress charges, see the [Pricing page](https://azure.microsoft.com/pricing/details/storage/files/).