Facing issues with ubuntu. I am unable to shut down it completely.
OK. Thanks for the info. 
We need more info.
For example,
Is it a laptop?
Can you look at the logs and see if there are any relevant messages?
What state is it in when you think it has not shut down?
Do you have hibernate or suspend activated?
How do you start it again ?
Neville
Welcome to the community.
Press and hold the power button while counting to ten. Then release the power button. Count to ten and press the power button, BUT only until you hear the fans start.
Why don’t you try using init 0 command to shutdown?