Excel usually does a good job second-guessing me when it chooses the scale for an axis on a chart. But sometimes, to better focus some data, I need to adjust that scale, and that’s when I run into problems if I don’t select the correct scale right at the start.
The easy way to make the adjustment to a completed chart is to right-click on the target axis, and that displays a screen with Format Axis (see screenshot).
Right-click on those words, and a full menu of size adjustments for the axis appears (see screenshot below).
Once you’ve finished adjusting the graph, consider copying the chart into Word, where you then can add finishing touches to it.