Which option must be selected when exporting a document from Microsoft applications to ensure accessibility?

Selecting "Document structure tags for accessibility" when exporting a document from Microsoft applications is essential to ensure that the document is accessible to individuals using assistive technologies. Document structure tags provide a semantic framework that allows screen readers and other assistive devices to interpret the content correctly, providing users with a better understanding of the information conveyed.

Including these tags helps define headings, lists, tables, and other structural elements, allowing for a coherent and logical reading order. When these tags are present, the document reflects its intended structure, enabling users with disabilities to navigate effectively and understand the relationships between different parts of the content.

The other options do not directly address accessibility. Saving a copy of the document does not impact its accessibility features. Restricting editing access may enhance document integrity but could limit collaboration and does not contribute to making a document accessible. Enabling offline editing is related to the document's availability for use rather than its accessibility features. Thus, selecting document structure tags is the primary action that directly influences how accessible the exported document will be.