There are two ways to convert a document to the PDF format:
‘Save As’ to save a version of the original document to a different format. Modern Office lets you make a PDF directly. This choice is sometimes called ‘Export’ or ‘Convert’.
‘Print’ which intercepts the printer output from a program to make a PDF file. Instead of a paper page coming out – a PDF file is created which looks like the paper pages. Both Windows and Mac have in-built options to do this from any program, not just Office.