JAWS means Job Access with Speech. It a screen reader that is used Chrome, Firefox, and Internet Explorer.
NVDA (Non-Visual Desktop Access) is a free Windows screen reader, that is portable via USB and downloadable. NVDA works best with Firefox and Chrome.
All mobile Apple devices come with VoiceOver installed. VoiceOver on iOS will read the operating system, web pages, and many of the Apple apps that come with the device.
There is also a version for MAC computers. https://help.apple.com/voiceover/mac/10.15/
Works best with Chrome. May not always be pre-installed but can get from Google Play. Explore by touch enables users to drag one finger around the screen to announce items as you reach them.
ChromeVox is a browser reader that only reads the Chrome browser, not the OS or any other software. On Chromebooks, the operating system is Chrome OS, so ChromeVox does read the operating system in that case, but the number and kinds of applications you can install on Chromebooks is limited. ChromeVox is not as full-featured as JAWS, NVDA, VoiceOver, Narrator, or Window-Eyes on web content, it doesn’t read ARIA as well as other screen readers, which is a disadvantage for dynamic web sites. ChromeVox is not commonly by blind users or by developers, but is sometimes used in testing non-interactive web pages.