Development should be done using aspnet boiler plate and devexpress/devextreme
Business logic is basically upload CSV file. Create a background task to process the CSV file and generate an excel file based on that csv file.
Eventually integrate it with aspnetzero and make it subscription based application.
21 freelancers are bidding on average $699 for this job
i am a lead .NET software engineer and responsible for creating a web and desktop applications using different languages and technologies if u r interested just send me a message thank you and good luck