How do I format my CSV file for Sell? What do the headers on my CSV file (import or export) represent?
The first row of the CSV file should reflect standard and custom fields. When you’re importing into Sell, they are useful for mapping your data. When you are exporting out of Sell, they reflect the names of standard or custom fields in your account.
For more information, see the article: Creating a CSV file to import leads, contacts, or deals.