TaxSlayer Pro provides the ability for your clients to set up a portal they can use to share documents that you need to prepare their individual tax return. The customer portal is also where they go to sign the E-File Signature Authorization (Form 8879, if electronically filing) or the tax return itself (if paper filing), and if they are utilizing a bank product to facilitate their refund transfer they can also sign the bank product application and the consent forms.
If one of your clients has forgotten where to go in their web browser to log in to their portal, you can give them this URL: