A visualization is a graphic representation of your findings, making it easily comparable and understandable. The visualization presents the findings in a clear and simple way. You need to understand what your data says and who your audience is in order to create an effective visualization.
Representing information in a chart, diagram, or picture is particularly useful for large amounts of information and for making patterns in data legible. If you are starting off with your data in csv format or Excel, you can make use of some of the tools in Excel.