How to Change File Format
In this tutorial I will be detailing how to change your file format for such things as documents and images.
Use a Website
Probably the most reliable way would be to use a converter website such as the one in the screenshot. This website will ask what you are trying to change the file to, then redirect you to the page where it done. All you need to do is upload the file and it will do it for you.
Do It Yourself
You can also rename the document and change the extension yourself. This may cause the file to not work properly so exercise caution when trying this approach.