The default rule is that the author is the owner of the copyright to a work. Because of this, publication agreements commonly require you to assign your entire copyright over to the publisher in exchange for publishing your work. This means that, upon signing such an agreement, the author(s) loses all control over their work in exchange for publication. Their work would then belongs to the publisher.
However, publishers do not actually need to own a copyright to publish an article. Instead, they only need certain rights to distribute the work. As the author, you can to negotiate to keep your copyright and instead give the publisher a limited license to distribute the work.
In deciding whether or not you are willing to transfer your entire copyright to a publisher, consider what you want to do with your work besides have it published. Retaining ownership of the copyright ensures that you will be able to do all of the following without constraints:
Be sure to carefully read your publication agreement to see if things like these are included. If they are not, and you would still like to retain them, try to negotiate with the publisher. See Understanding and Negotiating Book Publication Contracts (from the Authors Alliance) and the SPARC Author Addendum.
Below is a list of some author's rights resources that you may be helpful to you: