Recommended · for beginners
Fritzing - An Introduction
Why people recommend it
Introduces Fritzing, the open-source tool for breadboard layouts, schematics and simple PCBs; suggested for beginners who want diagrams that match their breadboard.
In their words
Printing your own PCB is fairly easy using Fritzing
Federico Fissore on arduino.stackexchange.com, Nov 2014. CC BY-SA.