Draw.Io
Diagrams for everyone, everywhere.
draw.io is an open platform where you can create and share diagrams. I use this when documenting flow charts for process mapping. If you want to capture your processes in an easy to understand and explain format then using a flow chart is the best solution. You basically are creating a picture of how your process works, and a picture speaks a thousand words.
At Balanced Leadership Center, we use draw.io for creating process map flow charts and functional/project organization charts.