Inkscape is vector graphics software that can be used to design and manipulate images to be sent to a laser cutter. It can also be used to create sketches that can be imported into 3d design software.
A wide range of capabilities makes Inkscape a very useful and powerful program to learn for many rapid prototyping techniques. The fact that it is open source software means that there are many user designed extensions available, and it is even possible to write simple programs to automate many processes involved in creating designs.
Inkscape is open source software, anyone can download and install it for free on their personal computer.
Install Link: https://inkscape.org/en/download/
Inkscape includes official interactive tutorials via Help menu > Tutorials. There are also many free online tutorials and instructions, for a brief list see https://inkscape.org/en/learn/.
For more information on using Inkscape with a laser cutter, see instructions in Laser Cutting.