E-book formats are digital file types designed for reading on electronic devices. Common formats include EPUB, which is widely used for its flexibility and compatibility with various e-readers, and PDF, known for preserving the layout of printed documents. Other formats like MOBI and AZW are specific to Amazon Kindle devices, offering features like adjustable text size and built-in dictionaries. Each format has its advantages and limitations. For instance, EPUB supports reflowable text, making it easier to read on different screen sizes, while PDF is ideal for documents that require precise formatting. Understanding these formats helps users choose the best option for their reading preferences.