Many web browsers provide extra features to make web browsing more accessible for those with special needs
These features can include keyboard shortcuts, altering page colors, fonts and font sizes, zooming capabilities, screen reader capability, and controlling web content, including pop-ups. This features can be inbuilt or with Chrome and Firefox take the form of browsers add-on/extensions. This Wikipedia page compares a limited number of accessibility features of a variety of different browsers.
The Chrome Browser section on this page explores accessibility features. There is a dedicated section on the Chrome Web Store for accessibility extensions. These tools will, for example, convert text to speech, enhance colors, and enlarge text and other parts of pages.
This page describes Firefox's inbuilt accessibility features. Before Firefox 57 (Firefox Quantum) there was as a good a selection of accessibility tools for Firefox as there is for Chrome. After Firefox 57, not so much. However, the Access Firefox website is a good source of accessibility tools and resources (some of which, sadly, may no longer work with Firefox 57 and later versions).
This page describes Internet Explorer's accessibility options. There are very few extensions for Internet Explorer
This page describes Microsoft Edge's accessibility options. There are very few extensions for Microsoft Edge.
Opera did once have a reputation as the most accessible browser, and the Opera site did have a dedicated page describing accessibility options, but no more. This page, which is a few years old now, describes how to turn on accessibility features on Opera. Like Chrome, the Opera add-ons site has an accessibility section
The Apple support page describing Safari's accessibility options has diasppeared from the Apple Website. This is a cached version of the page While there is a Safari extension gallery, there is no accessibility section.