What are the different options for outputting PDF documents using fpdf, and when should each option be used?

When using fpdf to generate PDF documents in PHP, there are several options for outputting the PDF file. The most common options include saving the PDF file to a server directory, streaming the PDF file to the browser for immediate download, or displaying the PDF file inline within a web page using an iframe or object tag. The choice of output method depends on the specific requirements of the application, such as whether the PDF file needs to be saved for later use or displayed to the user immediately.

// Example of saving the PDF file to a server directory
$pdf->Output('output.pdf', 'F');

// Example of streaming the PDF file to the browser for immediate download
$pdf->Output('output.pdf', 'D');

// Example of displaying the PDF file inline within a web page using an iframe
$pdf->Output('output.pdf', 'I');