Open access articles are published under a Creative Commons license. Moving from "All rights reserved" to "Some rights reserved", Creative Commons helps authors legally share their knowledge and creativity to build a more equitable, accessible, and innovative world. Under CC license, the author always retains the copyright of the works.
There are many types of licenses under Creative Commons, among which CC BY (Creative Commons Attribution) is the most popular one. OA articles published under the terms of CC BY license permits others to use, distribute and reproduce in any medium, even commercially, as long as the original work is properly cited. Always check publisher's copyright and licensing policies before you publish in open access (see an example from Wiley).