Cura is the software developed by Ultimaker to make 3D printing as easy and streamlined as possible. It includes everything you need to prepare a 3D file for printing and to print it. Cura is fully preconfigured to work on the Ultimaker. This is the software that speaks to the Ultimaker printre and converts the .stl files into .gcode (which is what the printer reads)
What is Cura?