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.

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

Business English is English language especially related to international trade. It is a part of English for Specific Purposes and can be considered a specialism within English language learning and teaching; for example, the teachers' organisation IATEFL has a special interest group called BESIG wikipedia.org

SEO content is any content created with the goal of attracting search engine traffic. wikipedia.org

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

Writing in these forms or styles is usually written in an impersonal and dispassionate tone, targeted for a critical and informed audience, based on closely investigated knowledge, and intended to reinforce or challenge concepts or arguments. wikipedia.org

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

Wikipedia is a collaboratively edited, multilingual, free-access, free content Internet encyclopedia that is supported and hosted by the non-profit Wikimedia Foundation. wikipedia.org