The only font that can be adjusted within Proclaim Desktop view, is the font within the case history.
To achieve this, follow the steps below:
For Proclaim version 4 onwards
From within the history, click the Table Setting cog.
Click Display Large Font.
Versions before Proclaim version 4
Select Choose Columns at the bottom of the history (the button may be named “Config Browse” in older versions).
Tick the Large Font? tick box.
Click the large tick at the bottom right of the window to accept the changes.