We know what “formal” education is. As the president of the Réseau said, it's schooling from kindergarten to grade 12, and then college or university, in other words, learning where recognized credits are given out.
“Non-formal” education is organized. It could be a training session that an organization or an entrepreneur organizes for their employees. As the president mentioned, it's also everything people get on YouTube, or a downloaded training session or tutorial. It's organized, in the sense that people have an appointment at a certain time for the training.
“Informal” education happens day to day and isn't organized. It's the information you share sitting with colleagues, for example. It's what people learn from each other.
All these are therefore organized in a continuum, and when everything comes together you get pretty amazing synergy.