Facetime for iPhone 4s not in the device?

I can't find it unlike the ipad.

When you make a call the icon will be there

The iPhone 4S doe not have a FaceTime icon unlike an iPad does. To facetime with someone, go to your Contacts, find the person you want to FaceTime, edit the contact and set the FaceTime info (email or number), then save and tap "Factime" Home or Email.