Setting up an email address with your company's domain name is essential for small businesses to establish their brand identity and maintain control over communication and accounts. Using a free email address can make the business look amateurish and harder to manage as it grows, whereas having a custom domain-based email address provides branding consistency, security, and control. By switching to an email hosting service like Google Workspace or Microsoft 365, businesses can keep using their preferred interface while enjoying the benefits of a custom domain-based email address.