Google Contacts, the address book built into Gmail, lets you keep track of all your contacts, see when you last interacted with them, and more.
File signed client agreements and email the team both links.
Your team gets links to the final signed agreement and its signing record, with both filed in the folder you choose.
Put the signing link and send confirmation in the client project.
Your client gets the agreement to sign, and you get the request link and send confirmation on the project.