When creating courses, there are eleven available lesson types that you can create. These lesson types include text, audio, video, web video, embed code, PDF, assignment, quiz, event, form, and waiver.
Each lesson type has specific requirements for content. For example, text lessons require a text field, while audio lessons require an audio upload.

Text: Description is required for this lesson type.
Audio: Audio upload is required for this lesson type.
Video: Video upload is required for this lesson type.
Web video: A video URL (from YouTube, Vimeo, and Wista)is required for this lesson type.
Embed code: Embed code is required for this lesson type.
PDF: PDF upload is required for this lesson type.
Assignment: Description is required for this lesson type.
Quiz: Questions are required for this lesson type.
Waiver: Agreement and consent statements are required for this lesson type.
Forms: Questions are required for this lesson type. This eliminates the need for third-party embedded forms.
How to use forms as course lesson
Learn how to add and use forms for Feedback & Assignments as a course lessons
Event RSVP: When created, it will be auto-populated with the linked upcoming and past events of the course.

Here is an article on how link an event to a course
How to link events to a course
Learn how to link events to a course