To export a 3D model for 3D printing, start by ensuring the model is watertight (no holes) and scaled to your printer’s build volume, then save it in a compatible format like STL or OBJ from your modeling software.
Use the software’s "Export" or "Save As" function—for example, Blender’s *File > Export > STL* or Fusion 360’s *Export > 3D Print > STL*—to create a file that retains only the model’s geometry.
Finally, import the exported file into slicing software (like Cura or PrusaSlicer) to convert it to G-code, the format your 3D printer can read.