The documents you upload here will only be shareable with the client in whose profile you stored them. If you'd like to learn how to add documents you can share with all of your clients, click here.
Go to your client's profile and click on the Store New Document on the right side of the page.
Select the file you'd like to upload and make sure you rename it so it's easy for you to identify.
Click on Share New.
You will now have the option to select any of your Stored documents to share with this client.