This essay provides a comprehensive overview of business communication theories, differentiating between internal and external communication methods. It explores various sources of communication, including reports, emails, and social media. The essay analyzes the communication practices of the Commonwealth Bank of Australia (CBA), highlighting its use of websites, mobile applications, and social media for effective communication with customers and the public. It also emphasizes the importance of effective communication in business operations and sales, while addressing common communication issues and barriers such as semantic and emotional barriers. The essay concludes with recommendations for improving communication, such as using simple language, adopting positive attitudes, and practicing active listening, with a focus on how organizations like CBA can implement effective communication strategies to overcome barriers and enhance business outcomes.