To directly answer your question, you can include both in your software release.
Release notes are a set of documents delivered to customers with the intent to provide a verbose description of the release of a new version of a product or service. These artifacts are generally created by a marketing team or product owner and contain feature summaries, bug fixes, use cases, and other support material. The release notes are used as a quick guide to what changed outside of the user documentation.
Conversely, changelogs are comprehensive lists of the new features, enhancements, bugs, and other changes in reverse chronological order. Changelogs usually link to specific issues or feature requests within a change management system and also may include links to the developer who supplied the change.