Some complex processes are hard to explain in text alone. A diagram can show the order of steps, who makes a decision and where a route loops back. I once wrote about Gliffy because it let you put shapes, arrows and words on a canvas without heavy design software.
Draw the question first
Do not begin with colors. Write down what the viewer should understand. For an order process, that might include the customer's choice, payment, dispatch and an exception for a wrong address. Put only the necessary steps in the diagram. An arrow should explain what happens; a tangle of lines merely recreates the original problem.
Ask someone unfamiliar with the process to describe what they see. If they stumble over an abbreviation or cannot understand a connection, change it. That is usually more valuable than adding another icon.
Today's Gliffy options
Gliffy says it no longer accepts new accounts for its standalone online tool. Existing users can continue; the company directs new users to its Confluence version. The old free trial and price from my article are therefore no longer a current route. The lasting lesson is to make the diagram understandable first, then choose a tool you can keep using and export your work from.