This technique is used when a message comprises different types of content or large volumes of data that need to be transmitted together. 

• Multiple Content Types: Multipart messages are often used to combine different types of content in a single message, such as text, HTML, images, audio, and video. Each part of the message is encoded separately but sent as a single unit.

• Use in Emails: In email, multipart messaging allows the sender to include both plain text and HTML versions of the message in a single email. Email clients can then display the version best suited to the recipient's email client capabilities.

• Multipart MIME Format: Multipart messages are typically structured using the MIME (Multipurpose Internet Mail Extensions) standard. MIME specifies how to format messages with multiple parts so that they are recognized and properly handled by email clients and servers.

• Handling Large Files in Messaging: For messaging protocols like SMS (Short Message Service), multipart messaging is used to handle messages that exceed the character limit of a single SMS. The message is split into multiple parts and reassembled at the recipient's device.

Multipart messages are essential in modern electronic communication, offering the versatility needed to handle diverse content types and large data volumes in a cohesive and user-friendly manner.