See the information on Kofax. Longer terms agreements may be reached with those that originate the paper and a digital process put in place to remove the printing / posting of a paper document all together. If you are the originator of the paper documents look at mechanisms that would allow you to email or, for more sensitive content, share documents from your document management solution.
Deltascheme have built a range of solutions from digital mailrooms for the scanning of inbound mail to document management solutions built on the Office 365 / SharePoint online platform to provide an extranet or place content can be safely shared. The use of the Security and Compliance Centre and Azure Information Protection can be used to add a further layer of security and control.