Samsung GALAXY S7 User Manual page 16

The battery comes partially charged. You can use the device while
charging.
Note: For fastest charging times, use the Adaptive Fast Charger that
came with your device. This charger provides faster charging only
when connected to devices that support Adaptive Fast Charging.
1. Insert the USB cable into the USB charger/Accessory port.
Caution: Use only charging devices and batteries approved by
Samsung. Samsung accessories are designed for your device to
maximize battery life. Using other accessories may invalidate your
warranty and may cause damage.
2. Connect the USB cable to the charging head, and then plug the
charging head into a standard outlet.
3. Unplug the charging head from the outlet and remove the USB
cable from the device when charging is complete.
Note: This device is also compatible with wireless charging devices
approved by Samsung, which are sold separately.
Set Up Your Device 7