Section Reports don't have the Comma-Separated Value (CSV) export option as RDL and Page reports do. However, there is a workaround to allow you to export your Section Report to a CSV.
Steps to Complete:
1. Section Report users can use the Plain Text (txt) export option.
2. The Plain Text provides export options to allow you to add a PageDelimiter, TextDelimiter, or QuotationSymbol to create a CSV file.