Standard digital fonts (TrueType or OpenType) are "outline" fonts; they define the boundary of a letter but are hollow inside.
For a "handwritten" look, use Hershey fonts which consist of single strokes rather than outlines. plotter
Most DIY or CNC plotters require a G-code file (the machine's "instructions"). Standard digital fonts (TrueType or OpenType) are "outline"
Watch these tutorials to see how to prepare script lettering and convert digital text into plotter-ready paths: Getting Script Lettering Ready for a plotter YouTube · Artwork Help plotter