COPY subquery INTO file_name - INCLUDE field name

Hi! We are using the COPY *subquery* INTO *file_name *[ [USING] DELIMITERS *field_separator* [',' *record_separator* [ ',' *string_quot*e ]]] [ NULL AS *null_string* ] BUT we need to have in the file the name of the fields on the first row. Im looking on the documentation, but I cannot find anything related to this, can someone help me with this? Thks in advance!