When uploading your Customer Data to Nosto using a .CSV file, the file must respect a certain format (CSV UTF-8 - comma separated) for correct data processing. You can download an example of .CSV file here. 

The majority of the CRM, Email Service Providers or Customer Data Management platforms offer an extensive set of functionalities, to select which data must be exported or also how to format such data. However, if you are facing some limitations or if you wish to format an Excel file to match Nosto's guidelines, we recommend you to read Microsoft Excel's official documentation here, providing all relevant information to correctly format your file to respect a CSV UTF-8 comma separated format. 

We recommend you to respect the following guidelines to create a CSV file from scratch: https://www.wikihow.com/Create-a-CSV-File