The Required Headers
In order to create an Excel file and make it downloadable instantly in PHP. I have used PHPExcel, and then I found it necessary to share these useful HTTP headers with you folks.
This specifies in what format the page should be rendered by the browser.
This header gives a default file name to the attached file served in the response.
Alternatively, one could sett X-Sendfile header and assign its value the absoulte path of the file to be downloaded. Then, x-send file module in Apache server should automatically initialize the optimum headers and serve the file.