Hello i ad admob banner to my app but when i test on my pc nothing is appening is it normal or do i have to be on a phone to test if it works?
Admob is for mobile only, does not work on PC. But even on mobile it is not always works. Not sure what is happening around AdMob but in HTML5/Cordova apps it is totally unreliable. 
so i have to publish on google play store to see if it works?
No you don’t, but you need to build the mobile app and copy on to your device and install it manually to test it.
EDIT:// when you do that, make sure the ad is set for testing otherwise Google going to ban you if you are watching real ads for your self.
oh ok ty i thought we couldn’t test on our mobile before adding the to google play store is there a tuto or somthing like that cause i don’t want to make mistake