When importing Customers in NetSuite, the fields on your CSV file depend on the fields that you have on your Customer entry form.
For a Standard Customer Entry form, the required fields are the following:
Subsidiary (for One World Accounts)
1. For Company-type customers, include the Company Name on the CSV file.
2. For Individual-type customers, include the following:
a. First Name
b. Last Name
c. Middle Name (Optional)