A teleseminar is where you listen only - there are no pictures to see or slides or anything like that. You can listen while driving, exercising, etc. without missing anything. You don't need to use a computer but can use your phone to connect.
Webinars would have the same audio content as a teleseminar but normally also has slides you watch during the presentation. You can't participate in this without looking at the screen to see the slides so listening while driving, running, etc. is out.
Depending on the setup you could participate in either live or recorded and you could ask questions if the presenter allowed them. Either may also have a summary or outline to look at before or after the training.