This is a broad topic for which I could talk for a long time - as a professional trainer. In short, you need to mix it up.
Live, in person, training;
Webinars;
computer based;
memo's;
staff meetings;
etc.
Some people learn better by reading, so by hearing, some by doing. Mix it up. Live training is more expensive, but more effective. Webinars are convenient & less expensive, but allow people to be disengaged. Training should be exciting. We typically learn more when we are having fun. That's why we entertain while we teach!