When we hear the term "accessibility" in the context of disability, the images that quickly comes to our minds are ramps, elevators, tactile paving (textured ground which helps vision impaired people navigate public spaces) or automatic doors etc. However, these are only physical examples.
There is Digital Accessibility which refers to the way people with a lived experience of disability interact with the cyber world. Some assistive technology tools like, Screen readers, high-contrast colour schemes and text magnifiers enable legally blind users to interact with websites, however, when websites uses e.g an image-based "CAPTCHA" test, without an inclusive approach then these tools are useless.
The World Wide Web Consortium's Web Content Accessibility Guidelines (WCAG) standard is universally available and it guides website and App developers on how to use web languages (such as HTML and CSS) in ways that enable end users who rely on assistive technologies. There is no special
technology or technique that is required to make websites or apps accessible, what we need is an adherence to good practice.