Files and Supporting Documents
Response page allows you to attach multiple types of files as supporting documents, including PDFs, Word documents, and Excel spreadsheets. You can quickly upload the supporting documents from your computer for the specific response.
To upload the supporting documents
Go to the Files section.
Click the Upload Files button or Drag and drop the respective document.
OR
Click the arrow icon beside the Files header and select the Add Files button.
A dialogue box appears with the Upload Files button, select files and click the Add button.

Click to enlarge
When user adds a new file on Response Version, all those new files will be also added(or linked) to the Response