A graph is a representation of a topic and shows the values usually in lines or bars. Mostly, a graph represents something that we count. We could count the numbers of blue and red cars in a street and show our findings in a graph.
Or the hectares of the rainforest.
Or the rainy days in a week.
Or our income or pocket money and the way we spend it.
Therefore a graph shows a relationship between characteristics (2 or more), with the means of a line, curve, bars or other symbols. Typically there is a horizontal line (x-axis) to represent an independent variable and a vertical line (y-axis) to represent a depending variable.
Chart is another word for graph.
BASIC CHARTS are bar charts, line charts, pie charts.
MORE ADVANCED CHARTS can be used to show more complex matters.
Remember:
There are many different kinds of graphs.
In general the graphs differentiate in usage.
Which form of graph you use depends on what you want to say or show.