Configure Wifi on Raspberry pi

sudo nano /etc/wpa_supplicant/wpa_supplicant.conf

My file is below for Raspian Stretch

ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1

network={
ssid="YOUR_NETWORK_NAME"
psk="YOUR_PASSWORD"
key_mgmt=WPA-PSK
}