When you have successfully enrolled, you will usually receive an email from the course provider. If you have enrolled before the course starts, you will receive another email with a link to the course when it begins.
You can then access the course material on the course provider’s website at any time of the day or night convenient for you.
This material is usually some combination of text to read, videos to watch, quizzes to complete, and assignments to work on. Many courses also have discussion forums. Some of the big course providers also have mobile apps, which can be used to access the course materials. Sometimes, course materials can be downloaded and studied offline.