Printing Dates on Photos
Click 'Date' on the 3. Layout/Print tab of the Print Setting screen and select 'ON' to print the date the picture was taken on the photo.
Reference
By clicking 'Options'..., you can change the text color, size and position of the date to match the orientation and background of the photo. Date Options Dialog Box
The date format depends on your OS settings.
Date Options Dialog Box
In this dialog box, you can specify the size and color of the date.
To display the Date Options dialog box, select Date on the 3. Layout/Print tab of the Print Setting screen and click 'Options'....