There are a few ways to do it but I know that when ites to free online services your file security may be at risk as the servers these services use may not be secured. Sometimes they even keep your files on their servers without deletion. One that does work and very good at that is SmallPDF - which can be accessed here s From personal experience I know that files there are deleted within an hour. They also specify that files are never opened checked or analyzed in any way. There also a all-in-one converter that you can convert other s of files within Microsoft Office as well as other cool manipulation tools that you should check out.