Comma Separated Value(s), also known as CSV, is a format to store structured data using text files. The CSV format is not standardized, so various implementations exist.
From those guidelines and giving the lack of standardization, the header line is optional in a CSV file.
When present, the header line must be the first line in the file and must contain the same number of fields as the records. Header and records lines must use the same field delimiters.
column_1, column2, column3 aaa, bbb, ccc 111, 222, 333