In newspaper terminology, a folio is a line of small text across the top of each page. The text includes the name of the newspaper, the date and the indexed page number to guide the reader. The line may also contain a heading to classify the content of the page.
Folios function as a date, source and page reference if the page is cut or torn out of the newspaper. For advertisers, full-page tear sheets, with folios included, are required from newspapers to prove that advertisements have been printed. Web publishers also typically provide a virtual tear sheet to advertisers, usually in PDF form.