When you create a web page or document which has well organized content it helps users to orient themselves and to navigate effectively.

Why is layout important?

A site or document which is well-structured is easier to understand and navigate.
Everyone can benefit from a site which is well-structured.
A well laid out page helps people with visual impairments, including low vision, orient themselves on the page and understand content.
Keyboard users can browse pages and their sections more efficiently.
People with cognitive and learning disabilities can more easily find and prioritize content on a well laid out page.
A well laid out page helps users perceive, operate and understand, POUR principles.

How to create good layout?

Citation: [W3C Web Accessibility Initiative (WAI)] ( 2016, May 17) Web Accessibility Perspectives: Clear Layout and Design (1:05min)

Audio Description version:
[W3C Web Accessibility Initiative (WAI)] ( 2016, May 17) Web Accessibility Perspectives: Clear Layout and Design - Audio Described Version (1:53min)