I was able to increase font for Editor. Need to increase size of Navigation Manager panel in Toad Data Point 5.1 if that is possible. Thanks.
Like many Windows applications, TDP relies mostly on Windows settings for its display fonts, so you'll most likely need to fiddle with the Windows OS font type/sizings to get fonts changed within most panels of Toad Data Point. The Editor has direct controls for font type and sizing within the Editor itself, but I think it and the data grid displays are about the only places that have direct control within TDP itself.
Like Gary says, it is not possible to change fontsize of individual features in Toad. Which version do you use? Until 5.1.2 it actually was possible to use dpi of e.g. 200% and it worked fine (although we do state we do not support dpi over 125%).
In the upcoming version we have enhanced the dpi scaling and it should work fine again on 200%