@ishwari-birajdar,
It is possible to use a scrollbar when there are multiple dataSeries needed to be shown on the toolTip. You can do so by changing overflow-y, height and pointer-events CSS properties of ‘canvasjs-chart-tooltip’ class as shown in the code-snippet below,
.canvasjs-chart-tooltip{
height: 100px !important;
overflow-y: scroll !important;
pointer-events: auto !important;
}
Kindly take a look at this updated JSFiddle for an example on scrollable toolTip.

—
Adithya Menon
Team CanvasJS