Open a document, then click on the page where you want to add the date and time.
To place it in the header or footer, move the pointer over the top or bottom of the page until you see the header or footer area, then click any of the three text fields (you can use any combination of the fields for your header or footer). To learn more about headers and footers, see in the bottom-right corner of the menu, then use the controls to change the date and time you want to appear in the field.
Note: By default, the date and time you pick appears in the selected field only. To change the date and time in all the fields in your document, click the Update All Fields button.