Documents or other files on your computer can be attached to the case using the 'Barcode' button. 
Using the Attach Icon
Click the 'Attach' button. An 'Add New Document(s)' panel will open.
...
Click on the Browse button and locate the document or file you wish to attach to the case. Note that the Browse function is operated by Windows and thus may vary depending upon the version of Windows installed on your computer. Once the file has been chosen, click on the Open or OK button. Multiple files may be selected simultaneously using this method, however all such files must have the same properties.
The file(s) will be uploaded to the case and an expanded 'Add New Document(s)' panel will open. The panel will list under 'Uploaded Files' the names of the file(s) to be attached to the case.
...
Choose the appropriate properties for the file(s) and click on 'Save'.
The attached files will be listed in the Document section of the case, with an Origin of 'Attached'.
...
About Attaching Documents
The Attach Documents button in the Quick Add Toolbar allows users to quickly add documents.
Select Attach.
Drag & Drop files from your local drive or
Browse and upload.
Confirm the Uploaded Files.
Select the Date and Time.
Select the Direction.
Select the Deliver method.
Select the Priority.
Select the Search Sub-Category.
Select the Category.
Select the Sub-Category.
Select the Tags.
Select the Folder.
Select where the Document is From.
Select where the Document is To.
Select the Related To.
Select the Analysis.
Select the Reviewed Date.
Enter a Description.
If applicable, place a checkmark in the Append file name checkbox.
Enter any relevant Comments.
Select SAVE to add new documents.
Otherwise, select CANCEL to return to the previous screen.
...