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 approved partnership agreements to their signers.
Your signers receive the partner agreement after final approval, and you see their invitation links beside the approval.
Send approved new-client agreements to the named signer.
Your client gets the agreement to sign, and you get the request link and send confirmation on the project.