wordpress Warning: Cannot modify header information - headers already sent by

  1. Open the file causing the warning in a code editor.
  2. Search for any characters (such as spaces, new lines, or symbols) outside of the PHP tags at the beginning and end of the file.
  3. If found, remove them and save the file.
  4. If the issue persists, check for any characters before the opening <?php tag or after the closing ?> tag.
  5. Ensure there are no echo or print statements before the headers are sent.
  6. Save the file and test to see if the warning has been resolved.