Create excel file using PHPExcel library

    $objPHPExcel = new PHPExcel();
    $objPHPExcel->getDefaultStyle()->getFont()->setName('Calibri');
    // set default font size
    $objPHPExcel->getDefaultStyle()->getFont()->setSize(8);
    // create the writer
    $objWriter = PHPExcel_IOFactory::createWriter($objPHPExcel, "Excel2007");   
    /**
     * Define currency and number format.
     */
    // currency format, € with < 0 being in red color
    $currencyFormat = '#,#0.## €;[Red]-#,#0.## €';
    // number format, with thousands separator and two decimal points.
    $numberFormat = '#,#0.##;[Red]-#,#0.##';
    // writer already created the first sheet for us, let's get it
    $objSheet = $objPHPExcel->getActiveSheet();
    // rename the sheet
    $objSheet->setTitle('My sales report');
    // let's bold and size the header font and write the header
    // as you can see, we can specify a range of cells, like here: cells from A1 to A4
    $objSheet->getStyle('A1:D1')->getFont()->setBold(true)->setSize(12);
    // write header
    $objSheet->getCell('A1')->setValue('Product');
    $objSheet->getCell('B1')->setValue('Quanity');
    $objSheet->getCell('C1')->setValue('Price');
    $objSheet->getCell('D1')->setValue('Total Price');
    // we could get this data from database, but for simplicty, let's just write it
    $objSheet->getCell('A2')->setValue('Motherboard');
    $objSheet->getCell('B2')->setValue(10);
    $objSheet->getCell('C2')->setValue(5);
    $objSheet->getCell('D2')->setValue('=B2*C2');
    $objSheet->getCell('A3')->setValue('Processor');
    $objSheet->getCell('B3')->setValue(6);
    $objSheet->getCell('C3')->setValue(3);
    $objSheet->getCell('D3')->setValue('=B3*C3');
    $objSheet->getCell('A4')->setValue('Memory');
    $objSheet->getCell('B4')->setValue(10);
    $objSheet->getCell('C4')->setValue(2.5);
    $objSheet->getCell('D4')->setValue('=B4*C4');
    $objSheet->getCell('A5')->setValue('TOTAL');
    $objSheet->getCell('B5')->setValue('=SUM(B2:B4)');
    $objSheet->getCell('C5')->setValue('-');
    $objSheet->getCell('D5')->setValue('=SUM(D2:D4)');
    // bold and resize the font of the last row
    $objSheet->getStyle('A5:D5')->getFont()->setBold(true)->setSize(12);
    // set number and currency format to columns
    $objSheet->getStyle('B2:B5')->getNumberFormat()->setFormatCode($numberFormat);
    $objSheet->getStyle('C2:D5')->getNumberFormat()->setFormatCode($currencyFormat);
    // create some borders
    // first, create the whole grid around the table
    $objSheet->getStyle('A1:D5')->getBorders()->
    getAllBorders()->setBorderStyle(PHPExcel_Style_Border::BORDER_THIN);
    // create medium border around the table
    $objSheet->getStyle('A1:D5')->getBorders()->
    getOutline()->setBorderStyle(PHPExcel_Style_Border::BORDER_MEDIUM);
    // create a double border above total line
    $objSheet->getStyle('A5:D5')->getBorders()->
    getTop()->setBorderStyle(PHPExcel_Style_Border::BORDER_DOUBLE);
    // create a medium border on the header line
    $objSheet->getStyle('A1:D1')->getBorders()->
    getBottom()->setBorderStyle(PHPExcel_Style_Border::BORDER_MEDIUM);
    // autosize the columns
    $objSheet->getColumnDimension('A')->setAutoSize(true);
    $objSheet->getColumnDimension('B')->setAutoSize(true);
    $objSheet->getColumnDimension('C')->setAutoSize(true);
    $objSheet->getColumnDimension('D')->setAutoSize(true);  
    // write the file
    $objWriter->save('filename.xlsx');