You can try the approach described at https://aps.autodesk.com/blog/merge-pdfs-svg-lines

That leverages BufferGeometry (refer to https://threejs.org/docs/#api/en/core/BufferGeometry) to draw geometries on top of the scene. Later, you can mimic those geometries as SVG and even print those in case of PDF files.

For text, you can leverage TextGeometry, as done in https://aps.autodesk.com/blog/how-do-you-add-labels-forge-viewer