E-learning is a structured course or learning experience delivered electronically; it can also include performance support content. There are also many different elements that can make up an e-learning program, such as live or pre-recorded lecture content, video, quizzes, simulations, games, activities, and other interactive elements.

Keep in mind that you may also see the term e-learning more broadly as a catchall for any learning content delivered electronically. While ATD style uses a hyphen in the spelling, you may also see it spelled elearning or eLearning. E-learning courses are typically managed and administered via a learning management system (LMS). As author, Steven D. Foreman notes in his book, The LMS Guidebook, an learning management system is "a multiuser software application, usually accessed through a web browser. It helps organizations manage training events, self-paced courses, and blended learning programs. It provides automation that replaces rigorous and expensive manual work, saves time, and enables you to organize your content, data, and learners. It tracks andreports on training activity and results."

The popularity of online learning continues to rise. According to ATD’s 2021 State of the Industry report, technology-based learning methods, including e-learning accounted for 80 percent of learning hours used in 2020.

Broadly, e-learning falls into two main categories: asynchronous and synchronous.

Asynchronous e-learning is self paced; the learners are taking the course on their own, usually on a laptop. Asynchronous e-learning programs may include pre-recorded lecture content and video, visuals, and/or text, knowledge quizzes, simulations, games, and other interactive elements.

Synchronous e-learning, more commonly referred to as live-online training, online learning, synchronous online training, or virtual classroom training, is instructor-led and taken at the same time as other learners – everyone just happens to be geographically dispersed. This training typically uses a web-conferencing or virtual classroom platform (such as Adobe Connect or GoToTraining) that offers features such as slide or screen sharing, as well as interaction tools such as chat, polling, and screen annotation.