What encoding should a CSV file have for correct reading through php?

Question

PHP

After uploading the CSV file to the server and trying to display its contents, I experience problems with the encoding and see "cracks".
Further work with these data is required.
What encoding should be specified for the csv file before uploading to the server, so that php correctly displays its contents?
Maybe you can just specify in the code what encoding is used?

If I just needed to display the content, I would write: for the appropriate encoding. But in the future I work with the contents of the file (its line-by-line moving to the data array). Which complicate the task.
header('Content-Type: text/html; charset=UTF-8');

Answer 1

Now it is customary to write php code in utf-8 and give site pages in utf-8.
If the csv file is in a different encoding, recode it using iconv or similar.
$str = iconv( "Windows-1252", "UTF-8", $str );

Answer 2

But in the future I work with the contents of the file (its line-by-line moving to the data array). Which complicate the task.

In fact, on the contrary, it simplifies. It is enough to look at the documentation for the fgetcsv parsing CSV function and see that the encoding for it is determined by the server locale settings.