phpdocx enables a webserver to take a docx document as input, then manipulate it and spit out another docx file or pdf.

For instance, I could create an invoice in Word with all the formatting etc but instead of the actual content like client details and amounts, I change those to variables like $client_name$ and $invoice_total$. phpdocx calls that a template. Then in the PHP code, I replace those variables with the texts that I need enabling the webserver to create an invoice with all the right information but keeping the flexibility to make quick changes in the look&feel of the document without having to do coding.