Set Background cell color in PHPExcel

Here is how you do it in PHPSpreadsheet, the newest version of PHPExcel

$spreadsheet = new Spreadsheet();

$spreadsheet->getActiveSheet()->getStyle('A1:F1')->applyFromArray([
    'fill' => [
            'fillType' => Fill::FILL_SOLID,
            'startColor' => [
                'rgb' => 'FFDBE2F1',
            ]           
    ],
]);

alternative approach:

$spreadsheet->getActiveSheet()
    ->getStyle('A1:F1')
    ->getFill()
    ->setFillType(Fill::FILL_SOLID)
    ->getStartColor()->setARGB('FFDBE2F1');

$objPHPExcel
    ->getActiveSheet()
    ->getStyle('A1')
    ->getFill()
    ->getStartColor()
    ->getRGB();

  $objPHPExcel->getActiveSheet()->getStyle('B3:B7')->getFill()
->setFillType(PHPExcel_Style_Fill::FILL_SOLID)
->getStartColor()->setARGB('FFFF0000');

It's in the documentation, located here: https://github.com/PHPOffice/PHPExcel/wiki/User-Documentation-Overview-and-Quickstart-Guide

You can easily apply colours on cell and rows.

$sheet->cell(1, function($row) 
{ 
  $row->setBackground('#CCCCCC'); 
});

$sheet->row(1, ['Col 1', 'Col 2', 'Col 3']); 
$sheet->row(1, function($row) 
{ 
  $row->setBackground('#CCCCCC'); 
});