To export a DataTable to CSV in C#, you follow a systematic process. First, you define the CSV format, which involves separating columns by commas and rows by newlines. Next, you iterate through the DataTable, accessing and extracting the data from each row and column. As you traverse the DataTable, you construct the CSV content by concatenating the values of each column with commas, creating rows of data. Once the CSV content is created, you can save it to a file or stream. This process ensures that the DataTable's data is accurately represented in the CSV format, ready for storage, sharing, or further processing in other applications or systems.