"...a complete and public draft of a scientific document. Preprints are typically unreviewed manuscripts written in the style of a peer-reviewed journal article. Scientists issue preprints to speed dissemination, establish priority, obtain feedback, and offset publication bias."
An author’s final manuscript, which has been peer-reviewed (if applicable to the publisher's policies). It has not, however, been copyedited nor does it reflect any layout by the publisher in preparation for publication.
"where a scientist publicly declares key elements of their research protocol in advance. Preregistration can help scientists enhance the rigor of their work."
Preprints and postprints (also called the author's final manuscript or author's accepted manuscript) can be posted in repositories (i.e., RED, PubMed Central). Often, researchers can share and/or retain the rights to these versions of their manuscript.
Sherpa Romeo can assist researchers in understanding their rights for archiving these versions of their manuscript and understanding publishers' policies.