Any document related to the request can be attachment to the request. The attachments can be uploaded while creating a request or you can add attachment while updating a request.
To add attachment from the Request Details page,
Click on the Request tab in the header pane to open the request list view page.
Click the Subject of the request to which you would like to add attachment.
From the request details page, select More Actions drop down and select Add Attachment option. The File Upload window pops up.
Click Browse button and select the file to be attached.
Click Open button. The selected file get attached to the request.
If you have more than one file to attach repeat steps 3 to 5.