Google Drive is Google's file sync app that lets you store all of your files online alongside your Google Docs documents, and keep them synced with all of your devices.
Keep purchase workflows moving after suppliers sign agreements.
Keep purchase requests moving after suppliers sign. Your confirmation form records the signed agreement link and closes the signature step.
Keep vendor proposal reviews moving with a logged request for each file.
Your reviewer gets a request for a decision, while the proposal item shows which file went out and when.