To export data to Excel in a CakePHP application, you can use the PHPExcel library. PHPExcel is a PHP library that provides a set of classes for reading and writing various spreadsheet file formats, including Excel.

To use PHPExcel in a CakePHP application, you will need to do the following:

1. Install PHPExcel: Use Composer to install the PHPExcel library by running the following command:

composer require phpoffice/phpexcel

2. Load the PHPExcel library: Load the PHPExcel library in your CakePHP controller by adding the following line at the top of the file:

use PHPExcel;

3. Create the Excel object: Create a new instance of the PHPExcel class and set the properties of the Excel document, such as the document title and the data to be exported. Here is an example of how you can do this:

$excel = new PHPExcel();
$excel->getProperties()
  ->setCreator("Your Name")
  ->setLastModifiedBy("Your Name")
  ->setTitle("Excel Document Title")
  ->setSubject("Excel Document Subject")
  ->setDescription("Excel document generated by CakePHP.");

// Set the data to be exported
$excel->setActiveSheetIndex(0)
  ->setCellValue('A1', 'Column 1')
  ->setCellValue('B1', 'Column 2');
$excel->getActiveSheet()->fromArray($data, null, 'A2');