You can change the font and point size of all the text that appears on Prism graphs:
•Set the default for fonts used in new graphs on the New Graphs tab of Preferences.
•The font of the graph title and axis titles can be changed by selecting the title, then changing the font using the toolbar or Change..Selected text. You can also change these fonts on the last tab of the Format Axes dialog.
•The font of legends is changed by selecting and changing using the toolbar or Change..selected text.
•To change the font of the axis numbering or labeling: Click once to select the axis. Then use the toolbar or change selected text to change the font of all the numbers or labels on that axis. You can also do this on the last tab of the Format Axes dialog.