Samsung Galaxy S4 User Manual page 319

Deactivating Wi-Fi
1. From the main Settings page, tap Connections tab.
2. In a single motion touch and slide the Wi-Fi slider to the left to
turn it off.
– or –
Activate and Deactivate Wi-Fi from the Notification bar.
Note: Use of wireless data connections such as Wi-Fi and Bluetooth
can reduce battery life and use times.
Connections 311