To create a custom graph in MATLAB that includes peaks on a quadratic curve, users can combine functions to achieve the desired effect. A simple quadratic curve can be plotted using the code: x=0:.5:20; y=(x-5).^2+10; plot(x, y). To add peaks, a Gaussian function can be introduced. For example, a Gaussian peak can be defined with y1 = 25*exp(-((x-10).^2)/0.5); and then combined with the quadratic curve using y2 = y + y1. The final plot can be generated with plot(x, y, x, y1, x, y2). Users are encouraged to add more Gaussian layers for additional peaks, enhancing the complexity of the graph. This approach allows for customization and flexibility in visualizing data in MATLAB.