A free certificate of completion is available for every course at learn.saylor.org by passing a course's final exam with 70% or better. Your digital certificate can be shared privately or publicly, linked to from other websites, downloaded to a PDF file, and printed.
We work with a certification provider called Accredible to issue and maintain certificates.
The latest details about our certificates and a live example can be seen here: https://www.saylor.org/accredible-certificates