If you have a National ID , then write the ID NO into the place, if not write N/A.That is why it say's, if applicable.
For Example, in the UK people do not have and carry a National ID, whereas in a Country like Germany, we all have National ID card's and are supposed to carry it on us at all time by Law. So, UK National's will put in N/A, while German Citizens will put in the no.
Do people from India put N/A for Identity card number ? I am sure you all have some sort of Identity card in India.
Is this field some thing to be filled by those applying from within Canada and the Identity Card refers to some thing issued by a Canadian
authority ?
In India we have cards for Voting, taxes etc but no single identity card. Unique ID project has just begin in India and will take time before every one has a identification number