Copywriting is the use of words and ideas to promote a person, business, opinion or idea. wikipedia.org

An electronic book is a book-length publication in digital form, consisting of text, images, or both, readable on computers or other electronic devices. wikipedia.org

An electronic book (variously, e-book, ebook, digital book) is a book-length publication in digital form, consisting of text, images, or both, and produced on, published through, and readable on computers or other electronic devices.

Lead Magnet is an offering of a specific chunk of value to a prospect in exchange for their contact information.

E-learning comprises all forms of electronically supported learning and teaching. The information and communication systems, whether networked learning or not, serve as specific media to implement the learning process. wikipedia.org

Instructional Design (also called Instructional Systems Design (ISD)) is the practice of creating instructional experiences which make the acquisition of knowledge and skill more efficient, effective, and appealing.

Professional writing involves the use of clear language to convey information in a way that is easily understood by the intended audience. Individuals who can use language well may be employed as full-time professional writers in a variety of communications-related occupations, such as wikipedia.org

A ghostwriter is a professional writer who is paid to write books, articles, stories, reports, or other texts that are officially credited to another person. wikipedia.org

Content marketing is a form of marketing focused on creating, publishing and distributing content for a targeted audience online. wikipedia.org