When an article is accepted, authors are usually asked to sign a copyright transfer or licensing agreement. This agreement defines how the article may be distributed and shared. Publishers may impose restrictions on the terms concerning postings of the final published versions of submissions to protect the sustainability of the journal. Many university press journals allow authors to share preprints or accepted manuscripts under certain conditions, often with required citations or embargo periods. Authors are encouraged to review their agreements carefully and consult publisher policies to understand what forms of sharing are permitted.
—AUPresses Faculty Outreach Committee
See also “What is copyright and why would a publisher ask to retain it?”