You can purchase e-books from online retailers or download free e-books that are in the public domain. Online retailers automatically send purchased e-books to your e-reader device via its Wi-Fi or wireless cellular network connection. E-books from other sites may need to be downloaded manually, depending on your e-reading device.
Individual e-book retailers, such as Amazon.com and Barnes & Noble, sell e-books that are meant to be used with their specific e-reading devices or by using their downloadable apps for other devices (e.g. computers, tablets, mobile phones). Amazon.com uses a proprietary MOBI e-book format, while most other e-book retailers and e-reading devices use the EPUB e-book format. It’s important to know what type of e-book file is compatible with your e-reader before downloading e-books from third party or public domain sites.
Books in the public domain, including thousands of literary classics, are readily available for free from both online retailers and websites such as Project Gutenberg. If your e-reader does not have a wireless connection, or when downloading from some third party websites, you may need to first download e-book files to a computer and then manually transfer them to your e-reader using a USB connection. Some retailers, such as Amazon.com with its Kindle e-reader, allow you to email e-book files and other documents to your e-reader.