The date is automatically included in the meta-data when you take a photo with your iPad. If you have a cellular model it will also geotag your photos, if location services are on and enabled for the Camera.
Unfortunately there is no way to see this data in the Photo or Camera app.
If you have iPhotos you can tap the (i) info icon while viewing a photo to see the date, location, and some of the other data. There are other apps that should let you do this, but I'm not sure which ones.
The good news is that the date and geotag data will (almost always) stay with the photo when you copy, upload, email, or otherwise transfer it off the iPad; where the receiving site or computer can make use of it.