How do I know if my request has generated volume?

You have two options.

If you see a white space or a zero in the "Google Volume" column, this means that there is no volume associated with your search query or that it is currently being collected.

If you see the crossed-out Google logo in the "Google Volume" column, this echoes the "No Data Google Policy". This means that Google does not provide any data on this term for various reasons (legal, moral, etc.).