Providing a descriptive title for the document will help users identify the document without having to interpret page content.
To add a title to a document, right-click the failed "Title" check in the Accessibility Checker panel and click "Fix." Uncheck the "Leave As Is" box and enter a descriptive title for the document. Click the "OK" button to save the document's title.
To manually set the title, click "File" in the main menu and select "Properties." Give the document a descriptive name and type it in the "Title" field. Click the "OK" button to save changes.
WCAG requirement: 2.4.2 Page Titled