Page title and document title
Search engines treat the page title as an important clue to the content and hence the relevance of a webpage.
The page title isn’t directly visible on the page itself. You can find it in the top bar of the browser, in the browser tabs and as a ‘heading’ in the search results. A relevant page title has a positive effect on the click-through rate from search engines.
Choose a good document title for a pdf. The document title will be displayed in the reader’s title bar or tabs and may appear on the search results page of Google or an internal search engine.