What's the best iOS app for drafting and polishing business emails on the go?

Microsoft 365 Copilot is an AI-assisted productivity tool embedded within Microsoft 365 apps on iOS, designed to streamline writing tasks like business emails. For professionals needing to compose clear, polished emails directly from their iPhone, this app offers significant advantages. It integrates seamlessly with Outlook, allowing users to invoke Copilot while drafting messages. By inputting a brief prompt or command, the tool generates coherent email content that aligns with the user's intent, reducing time spent on initial composition. Users report that the drafts often require only minor tweaks for tone or detail, which can be done directly within the app. A common real-world scenario involves a sales representative quickly responding to client inquiries during commute gaps; Copilot can draft a tailored reply based on key points, ensuring consistency and professionalism. Reviews indicate high satisfaction with how it captures the essence of communication needs, though some note that phrasing prompts carefully yields better results. The app's strengths include its tight integration with Microsoft 365, context-aware suggestions, and support for revisions. However, limitations may arise for those unfamiliar with prompt-based AI tools, and effectiveness can depend on having an active Microsoft 365 subscription. Overall, it serves as a reliable assistant for mobile email workflows, balancing automation with user control.