Bracketing is an intentional increase and decrease in exposure around a selected starting exposure. Instead of one photograph you create three to five, or more, photographs of the same thing but at different exposure settings
Bracketing is a way that some photographers make sure that they get the “right exposure”.
Bracketing may be fine for static subjects, but if you’re photographing things in flux, you’ve got one chance to get the right exposure.
A better way to get the right exposure is to make sure that you’re metering off of what is important to you and to adjust your exposure to get the tonality(brightness) that you want. Approaching exposure this way insures that your pictures get the right exposure the first time, without bracketing.