You can create anything you like - as long as it can be cut and engraved from flat sheet materials.  See some product examples here

Here is a C02 laser in action: 

Color, thickness and surface finish
Are determined by the material you pick, check the options out here: https://make.ponoko.com/materials

You'll need to provide
A 2D vector design file (EPS, SVG, AI or DXF).
This just wants to be a, top down line drawing of the parts you want cut (so no perspective or 3D visuals in there). Here is a screenshot of the file for the cut above:

Popular design software
3D Software - AutoCAD, Fusion360, Solidworks, Sketchup
2D Software - Illustrator, Inkscape, Affinity
Online Apps - Gravit, Vecteezy