How can I display the date on actual photos taken with iPhone?
DateCam S is a free app that will add the date to photos that you take automatically.


  This app simply adds date on your photos.
  
  So now, you can see when the photos were taken!


There are also apps that let you manually add any text (e.g. a date) to your photos. I have used and recommend Camera+ due to its stylistic formatting of the text.