Guys I kindly follow the instructions : (This method works on all Debian and Ubuntu based distro...)
1. sudo apt-get update && sudo apt-get upgrade
and then
sudo apt-get install linux-headers-$(uname -r)
(This part may vary from distro to distro)
2. Reboot your pc
3. git clone https://gitlab.com/archimanc/realtek-...
4. cd realtek-wifi-adapter-driver
5. make clean && make
6. sudo make install
7. sudo modprobe -r rtw_8723de
8. sudo modprobe rtw_8723de
9. sudo modprobe -r rtw_8723de && sleep 5 && sudo modprobe rtw_8723de ant_sel=4
10. echo "options rtw_8723de ant_sel=4" | sudo tee /etc/modprobe.d/rtw_8723de.conf
and then reboot the system and enjoy wifi..
cheers