Where is airplay on my iPhone 5s

you swipe your finger from buttom to top that give you a semi transparent menu which has the airplay feature

it's here over the camera icon

http://www.imobie.com/support/img/ios-7-control-center.png

Airplay will only show up if there is an Airplay capable device connected to your local WiFi network/Bluetooth.

Look in the Control Panel for Airplay. To access the Control Panel swipe up from the bottom of the screen.