The nice thing about charts is that it is easy to see how the stock acts from day to day or from week to week, or over a longer period of time. As an investor you can also keep track of the stock prices personally and make customized charts for your own interest. Charts can be displayed in many ways, but the most important is that they show and represent the changes that are of interest to the technical analyzer. Most charts show the closing value of the stock for each day, week or month. Some charts even show per minute or hour, but the importance of the charts is that they display the movement of the price of the stock, so that the analyzer can make a decision.
Many charts also show the high, low and closing price of the stock for each day.
How detailed the charts are are of different interest to different investors, depending on how volatile the stock is and how quick they want to make investment decisions. Charts can also exaggerate or misrepresent stock prices. If the scale of the chart is not customized, it might be difficult to see how well or bad it is performing. Most investors like to manipulate the scales so that they easier can see how much the price is changing from day to day. Then it is easier to keep track of the price and how it is performing.