What is the purpose of a Heading 1 tag in a document's structure?

The purpose of a Heading 1 tag in a document's structure is to denote the main content heading. This tag is typically used to indicate the highest level of heading within a document, providing a clear and organized hierarchy of information. It serves as the primary title for the document or the main section of content, helping readers and assistive technologies, such as screen readers, understand the overarching theme or main topic of the information that follows.

Using the Heading 1 tag effectively helps improve navigation and accessibility, as it allows users to quickly locate and comprehend the key subject matter. In terms of document structure, it establishes a clear starting point for further subdivisions and sections within the document, effectively guiding the reader through the content in a logical manner.