https://www.tinkercad.com/

TinkerCAD is a web based 3D modeling application from AutoDesk. It is designed primarily for hobbyists and newbies who have little or no experience with 3D CAD. The tools are somewhat limited when compared to the professional vesions like SolidWorks or AutoDesk Invent but you can export STL files for 3D printing or SVG files for laser cutting.