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.
Send each ready asset to its reviewer and log the handoff.
Your reviewer gets the current asset with a clear request, and your campaign task keeps the handoff in view.
Put approved campaign assets where the launch team can find them.
Your campaign team gets a shortcut to the approved asset in its launch folder, with no handoff to chase.
Flag blocked campaign files before creative review begins.
Your review task shows file access problems before review starts. The owner sees what to fix.