Unfortunately browsers don’t currently support turning existing html content into webGL textures for numerous reasons including security worries, there are some proposals to solve this in the future but at present, the app needs to do the rendering itself.
I’d recommend using
- babylon’s gui: Use the Babylon GUI - Babylon.js Documentation
- html2canvas: https://html2canvas.hertzen.com/
- or manually drawing text on a canvas and using babylons dynamic texture to wrap the canvas: HTML Canvas Text