If you've issued an Agreement to your client and it remains outstanding, there's a simple way to resend it.

To do so, visit Business Center >> Agreements >> Outstanding, and click on the Agreement you wish to resend.

In the pop up that appears, you'll find a send button (airplane icon) in the lower right.  Click that and you'll be able to send a note to your client about the outstanding Agreement, which will put them one click away from accessing and being able to complete it.