The QuickBooks Attached Documents Feature seems to be handy, as it allows you to attach document(s) scanned or already on your computer to a transaction in QuickBooks.
It’s now a part of QuickBooks without needing a subscription, the files are stored locally where the company file is stored, in a sub-folder named Attach. You can drop a file in the document center (Top menu > Company >Documents >Doc Center) which causes the file to be stored in “…\Attach\Inbox” and then later you can attach it to a transaction, or you can attach a document to a transaction without having to put it in the inbox first.
To attach a document to transaction, whether already existing on the computer yet or not, open the transaction, then click the paperclip icon and make a selection of what you want to attach.
After a document that has been first put in the Inbox then has been attached to a transaction, the file physically moves to sub-folder of “…\Attach\Txn”. That sub-folder’s name is derived by some unique identifier. There is no report in QuickBooks that shows this identifier, so there’s no way to know what the folder in the Windows represents, although you can open the docs inside.
DO NOT rename the file in Windows otherwise the link with the QuickBooks database will be broken. If you must re-name, you will need to un-attach the document. Copy the document somewhere else first because it will be deleted upon detach. Then change the name of the moved file, , and re-attach to the transaction. You can detach/re-attach from the same screen as you attached the document.
To view the attached document, open the transaction, then click the paperclip icon and make a selection of what you want to attach, and click the Open button.
Other sources: http://dataservices.intuit.com/support/articles/sln58984