The CSV file must contain the header row and a number data rows. Each data row will be used to import a single user. Note that up to 1000 users will be imported from a single CSV file.The names of the header row will be used to map each CSV field into a user property. Beyond the standard user properties listed below, you can also add custom user fields that you can define on the Właściwości użytkownika page.

The standard user property names that you can use in the CSV file are as follows:

first name, last name, email - basic user information.
country, address, city, zip, state - user address data.
phone, phone country code, mobile number, mobile country code - phone numbers. You should specify country codes as fields separate from the number itself.
language - user language. Use two-letter language codes (ISO 639-1), like: EN, DE, FR, ES, IT, PL etc.
preapproved - to mark a user as preapproved, set the value of this column to preapproved
Note that the First name and email fields are obligatory. Other fields can be specified optionally.First name, Last name, email, country, city, phone, phone country code, language
John, Doe, jd@foo.com, England, London, 22334455, 44, EN