This feature allows an Auto Attach Path to be specified in User Preferences.  If set, when the Attachment screen is opened, it will auto attach any files in this folder.  If files are added to the folder while the Attachments screen is open, they will also be attached.  After files are attached, they are moved to an Archive subfolder.
Example: this is primarily useful if you scan in packing lists/invoices and you want to attach them to purchase invoices in Paradigm, etc.

To use the Auto Attach feature, first create a folder in your desired location for the Attachments that you want to attach to documents or line items in Paradigm.

Then go to System > User Preferences > User Defaults and populate the “Auto Attach Path:” field with the path of the folder you created. 

To attach files to a document in Paradigm, click the    button in the header.  To attach files to a line item, click the    button.  As stated above, any files that are already in the folder that you mapped in User Preferences and any files that you add to the folder while the Attachments window is open will show up in the Attachments list.

The    button in the header will display a combination of document and line item attachments, regardless of whether they were added through the Auto Attach feature or attached through “Add Attachment” in the Attachments window.