_____________ is an online communication that allows instant exchange oftext-based messages between a sender and a receiver.

The term you're looking for is "instant messaging."

Instant messaging (IM) refers to a type of online communication that enables real-time text-based exchange of messages between individuals or groups. This form of communication is prevalent in various platforms like social media apps, email clients, and dedicated messaging applications such as WhatsApp, Telegram, and Facebook Messenger.

Key features of instant messaging include the ability for users to send and receive messages in real-time, often accompanied by notifications. Many instant messaging services also allow for additional functionalities such as file sharing, voice and video calls, and the ability to create group chats.

The immediacy and convenience of instant messaging have made it a popular choice for both personal and professional communication, facilitating quick interactions that can enhance collaboration and connectivity between users.