Is there any way to curve the text box so you can place in the curvature of something like a ring to engrave
The text box curves itself but it is limited to a fraction of the arc in the case of something like a ring. At present it won't curve it over a full 360 degree span. Practically speaking it's going to be less than 180 degrees in this case.
The tool projects the box on the surface and then follows the contours of the object. So yes, that is automatic. It may not work with all surfaces, such as those having compound curves, but for simple curves it seems to work well. You should be able to try it with some models in your store to see how it works.