PhpSpreadsheet set background color of cell to white

By using a style array to set few styles at once:

styleArray = array(
            'borders' => array(
                'outline' => array(
                    'borderStyle' => Border::BORDER_THICK,
                    'color' => array('argb' => '00000000'),
                ),
            ),
            'fill' => array(
                'fillType' => Fill::FILL_SOLID,
                'startColor' => array('argb' => 'FF4F81BD')
            )
        );
$spreadsheet->getActiveSheet()->applyFromArray($styleArray);

In some examples, we find 'fill' instead of 'fillType'. Perhaps it depends on version of phpSpreadsheet. Another variant is 'color' instead of 'startColor'.

You don't have to include the # symbol when you specify the ARGB for PhpSpreadsheet. These solutions will be able to set the cell background to white:

Cell by cell

$spreadsheet
    ->getActiveSheet()
    ->getStyle($cells)
    ->getFill()
    ->setFillType(\PhpOffice\PhpSpreadsheet\Style\Fill::FILL_SOLID)
    ->getStartColor()
    ->setARGB('ffffff');

Range of cells

$spreadsheet
    ->getActiveSheet()
    ->getStyle('A1:A5')
    ->getFill()
    ->setFillType(\PhpOffice\PhpSpreadsheet\Style\Fill::FILL_SOLID)
    ->getStartColor()
    ->setARGB('ffffff');