Which document outlines principles for creating accessible content?

The Web Content Accessibility Guidelines (WCAG) is the primary document that outlines principles for creating accessible web content. It provides a comprehensive framework aimed at ensuring that web content can be accessed by all users, including those with disabilities. The guidelines establish a set of standards and best practices that can be applied to various types of digital content, such as websites and applications, promoting inclusivity and enabling equal access to information and functionalities.

These principles include aspects such as perceivability, operability, understandability, and robustness, which are essential for creating content that everyone can use effectively. By adhering to WCAG, content creators can identify and implement necessary improvements in their digital content, ultimately fostering an environment where inclusivity is prioritized.

The other options, while relevant in their respective fields, do not specifically focus on accessibility principles related to content creation. Thus, they focus on different areas of policy, usability testing, and marketing strategies rather than the guidelines for making content accessible to users with various disabilities.