Translation guide
The most common way to say 'e-book' in Japanese is 電子書籍 (denshi shoseki), a formal term used in publishing and retail. In casual conversation, people often just say 電子書籍 or use the English loanword イーブック (ībukku), though the latter is less common. For specific devices, 電子書籍リーダー (denshi shoseki rīdā) or 電子ブックリーダー (denshi bukku rīdā) are used.
Standard term for e-books in formal and technical contexts. Widely understood.
Lately, I often buy e-books.
You can read this novel as an e-book too.
Loanword from English. Used in casual contexts or in branding, but less common than 電子書籍.
It's cheaper to read it as an e-book.
Less common variant, sometimes used in product names or older contexts.
Please tell me about e-book formats.
Referring to the physical device used to read e-books.
電子書籍 is the safe, standard choice in most situations. イーブック is understood but may sound like a brand name or overly casual in formal writing.
Alternative term, also common.
E-book readers are easy on the eyes.