Negative space (sometimes also called White Space) is simply an area of "empty" space around the subject of your image. Space that is negative is usually either a neutral or contrasting background that draws your eye to the main subject of your photograph.
This neutral space can be creamy bokeh (which as we know is used a lot of portrait photography to let your subject stand out against the background) or open sky, grass, walls, or plain background etc - anything that does not compete with the main subject for attention by being too ”cluttered” and gives the viewer’s eyes a chance to rest.
So why do we use it? Having negative space in your image can help sharply define and emphasise your main subject by drawing the viewers eyes directly to it. It also helps create a feeling of space and calmness. I personally love images with negative space, as I love the simple uncluttered look.
Whether to have negative space or how much to use is a matter of personal style and is subjective - some photos work amazingly well with lots of negative space, others better with just a little ”breathing space”, and some with no negative space at all!
I think it's easier to describe negative space by using pictures rather than with words, so here are some examples of negatives space….
As you can see, each is subtly different in terms in what is used as negative space, and how much has been added - both of those things will be different for each photograph, depending on what you have to work with, how you wish your viewer to perceive the photograph, and simply how much is needed to create a pleasing balance.