What Is This? Windows Basics
12. Files
12.5. File Types
There are different types of files that you can save into folders. Some files are text documents, but images, videos and spreadsheets are also examples of files that you might create or receive and then wish to save in your folders.
For the computer to understand how to open the file, it reads a piece of code called a file extension. There are hundreds of file extensions but a few are in common use and listed here.
| File Extension | Description | Use |
| .doc or .docx | Word® document | Written materials. Can be edited. |
| Portable document format | Image of a written document that cannot be easily edited. If printed, will retain its formatting no matter what printer is used. | |
| .xls | Excel® spreadsheet | Data calculations and reports. |
| .ppt | PowerPoint® | In this version of the file extension, the presentation can be opened and edited. Other similar extensions are used for PowerPoints that open as a completed presentation or with some of the content hidden. |
| .mp3 | audio file | Music. There are many other audio and video file extensions but these versions are adaptable to many computers and media players. |
| .mp4 | video file | Video |
| .jpg | image file | Photos. Drawings and other images may use .png or .gif |
| .zip | archive file | Stores multiple files and compresses files. If you are sent a zip file, you must extract the files inside to view them. |
Note: There is a type of file with an extension: .exe This stands for executable file. It is a file that can make changes to an application or a program already running in your computer. You sometimes need to download an .exe file if you have purchased some software online or if that software or system needs to be updated on your computer. Unfortunately, this is also one of the ways that viruses and worms are introduced into your computer.
If you are sent an .exe file as an attachment, NEVER open it. If it appears to come from a friend, that friend's account may have been hacked or the friend may think they are sending you a funny joke or something cute and does not realize it may contain a virus. Only open an .exe file if you know it is from a reputable company from whom you have requested software or an upgrade. Check first with any friend who may have sent an .exe file to you in an email before you open the file.