In most PDFs, Chaupai Sahib refers to the 12 stanzas (from “Hamri karo hath dai racha” to “Dustt dokh te leho bachai”). However, in some traditions, the complete Kaviyu Bach Benti Chaupai (up to “Sabh thok tumre saad na aavai”) is included. A good PDF will clarify which version.
There is no single "official" centralized copyright for the Gurbani text itself, as it is considered sacred scripture in the public domain of the faith. Consequently, PDFs are widely available from various reputable Sikh organizations.