Sold non-MLS listings are useful for credit and market analysis comp purposes. 

If you represent a buyer on a non-MLS sale, you can submit this listing as a Sold Non-MLS listing after settlement. Sold Non-MLS input forms can be found in the Input tab of Matrix, in the Add New Listing section.

Sold non-MLS listings can be submitted any time until January 31st of the following year after the settlement date. These sales will reflect on the agent's production report. While some fields are still required, these listings do have as many mandatory fields as normal MLS listings. 

There is not a sold non-MLS form for rental listings.

It is not possible to input an off market, off-MLS sale as the listing agent unless you also represented the purchasing party.