Install Wi-Fi driver in Ubutnu 18.04 if it is not available in your machine. Especially needed in HP Laptops.

WiFi-Driver-Not-Found.sh

# If the Wi-Fi driver doesn't work in Ubuntu 18.04
# Run the following commands in your terminal one by one
# Inside the ~ directory

git clone https://github.com/lwfinger/rtw88.git
cd rtw88
make
sudo make install
sudo apt purge bcmwl-kernel-source
sudo sed -i '/blacklist bcma/ d' /etc/modprobe.d/blacklist.conf
sudo sed -i '/blacklist brcmsmac/ d' /etc/modprobe.d/blacklist.conf
sudo modprobe -r rtw_8723de
sudo modprobe rtw_8723de
sudo modprobe -r rtw_8723de && sleep 5 && sudo modprobe rtw_8723de ant_sel=1

# Once done, restart your machine
# You will be able to use the WiFi now on your machine.