Organize Your Folders and Files
Aside from manually dragging the folders and files by clicking and dragging the six dots, you can set your file sort order by Alphabetical: A-Z or User Sorted Order inside the Defaults & Settings of the transaction.
Manual Sort Order
You can drag and drop your folders and files according to your preference by clicking the six dots icon.
Document Sorting: Alphabetical: A-Z or User Sorted Order
The files inside the document folder can be sorted either in alphabetical order or by user sorted order. Inside the property, click the transaction details sub-menu then go to the Defaults & Settings. Look for the Document Sorting field and choose which sort order to use on your transaction.
IMPORTANT:
You can set this globally for your entire organization by going to Global Settings.