M4B is an audio file format primarily used for audiobooks. It is similar to M4A but supports bookmarking, allowing users to easily resume playback from where they left off. M4B files are compatible with Apple devices and apps, making them ideal for audiobook enthusiasts.
M4A is an audio file format developed by Apple, often used for songs and other audio content in iTunes. It is based on the AAC codec and offers high compression with minimal loss of quality. M4A is ideal for digital music files due to its smaller size and efficient storage.