Courseware is interactive reading and learning textbook material that will sometimes include quizzes, assignments, and further reading. Courseware can be found in your course directly on your LMS (Canvas, Blackboard, etc.), or it can be found directly on a publisher's website and accessed through registration with an access code. If you have ever had a textbook that had a code at the back of the book that allowed you to access addition content on the publisher's website, you have used courseware!
Some publishers will include the e-text directly within the courseware located on their website or integrated in your LMS, so if you are not sure why you haven't received a title in your library for your course, it could be because there is there is no separate e-book, and you will see that you have a code, or in your course you will find your courseware directly within your course shell.
If you aren't sure what type of textbook you have, please consult your professor to ensure that you are looking in the correct place for your textbook materials!
Here is an example of a publisher's courseware page where you would input your access code: