fieldnames = ['last_name', 'login'']

 list=[['Иванов', 'ivanov'],['Петров', 'petrov'], ['Сидоров', 'sidorov'] ]

  
import csv
 
with open('file.csv', 'w', encoding='utf-8', newline='') as fout:
    fields = ['last_name', 'login']
    writer = csv.DictWriter(fout, fieldnames=fields)
    lst = [['Иванов', 'ivanov'],
           ['Петров', 'petrov'],
           ['Сидоров', 'sidorov']]
    rows = [dict(zip(fields, i)) for i in lst]
    writer.writeheader()
    writer.writerows(rows)