Getting Started with 3D Printing
3D Printing Software
You will need two types of software for 3D printing: design software to create an object and slicer software to prepare it for the 3D printer.
Most 3D printers come with their own slicer software. (For more advanced users, there are many other options for slicer software.)
For design software, TinkerCAD and BlocksCAD are good choices for working with children.
3D Printing Filaments
There are many different types of 3D printer filament. The two most common are PLA and ABS. For working with children, PLA is generally your best bet: it extrudes at a lower temperature than ABS, produces fewer fumes, and is more environmentally friendly.