The FabLab offers access to 3D printers: https://fablab.uta.edu/equipment/3d-printing, and we are happy to help you learn how to 3D model to bring your imagined designs into the real world!
There is a huge ecosystem of 3D modeling programs that can be used to create designs for 3D printing.
If you have no prior 3D modeling experience, we recommend starting with TinkerCAD.com
More advanced software such as Solidworks, Fusion 360, Rhino, Maya, 3DS Max, Blender, Meshmixer, OpenSCAD, FreeCAD (and many more!) may be appropriate depending on your project goals and level of patience for learning the tools.
The important thing is that you need to be able to export a watertight/manifold mesh as an .stl
