Enter sudo raspi-config in a terminal window. Select Interfacing Options. Navigate to and select SSH. Choose Yes. Select Ok. Choose Finish.
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev update_config=1 country=<YOUR TWO LETTER COUNTRY CODE> network={ ssid="<YOUR NETWORK NAME>" psk="<YOUR NETWORK PASSWORD>" key_mgmt=WPA-PSK } save this in "wpa_supplicant.conf"