Everyday Computer Skills · Documents, PDFs & Printing · Lesson 1 of 5

Documents and File Types

Learn what Word, Docs and Pages make, and why PDFs look the same.

What a document is

A document is a file you write in, like a letter, a list or a form. A file is one saved item on your computer.

You write documents in a word processor. A word processor is an app for typing, fixing and arranging words on a page. Three common ones are:

• Microsoft Word, which comes with Microsoft 365 and is common at work.
• Google Docs, which is free and works in a web browser. A web browser is the app you use to visit websites.
• Pages, which is free on a Mac, iPhone and iPad.

Every file has a name and a file type. The file type tells the computer what kind of file it is. It shows as a few letters after a dot at the end of the name. These letters are called the file extension.

Here are three you will see often:

• .docx: a Word document. You can change the words easily.
• .pdf: a finished page meant for reading, printing or signing.
• .txt: plain text. Just letters, with no bold, pictures or colors.

If you don't see the letters after the dot, that's normal. Windows often hides them. Each type also has its own little picture, called an icon.

Opening a PDF

PDF stands for Portable Document Format. It is a file type made so a page looks the same on every device.

Why does that matter? A Word document can shift when someone opens it on another computer. The letters might change, or a picture might jump to the next page. A PDF keeps everything in place. The fonts, pictures and page breaks stay exactly as they were made.

That is why tickets, bills, bank statements and forms often come as PDFs. They look the same on a phone, a laptop or on paper.

To open a PDF, double-click it. To double-click means to click twice quickly. On Windows, it usually opens in Microsoft Edge, the web browser that comes with Windows. You can read it, zoom in, print it, and often fill in forms.

On a Mac, a PDF opens in Preview, the app that comes with every Mac.

PDFs are harder to change than Word files. That is on purpose. If you need to change the words, ask the sender for the original document.

You don't need to buy anything to read a PDF. Free apps can open them. Be careful with websites that ask you to pay just to open one.