An MCPD (Microsoft Certified Professional Developer) developer is a certified professional who specializes in designing, developing, and deploying applications using Microsoft technologies. Their tasks include writing code, debugging software, designing user interfaces, and optimizing systems. They work on various platforms such as Windows, Web, Enterprise applications, using languages like C#, .NET, ASP.NET, and SQL Server. They are also involved in decision-making processes related to software development strategies and can lead teams to complete projects. Their certification ensures they are well-versed with the latest Microsoft technologies and can effectively work on complex development tasks.