2  2. Working with files

2.1 Mac Finder and Windows File Explorer

The Finder app on Mac and the File Explorer app on Windows are used to navigate the files on your computer. You should become familiar with how to use those apps on your computer. For more info search online. Youtube videos are often a good way to learn about how to use these features.

2.2 Filename extensions

2.2.1 What is a filename extension?

A filename extension is the portion of the filename that appears after the final period. For example, in the file LetterToBob.docx, the filename extension is .docx. In a file named finances.xlsx, the filename extension is .xlsx.

2.2.2 A filename extension indicates which program should be used to open a file

Modern Microsoft Word documents have a .docx filename extensions (older versions of Microsoft Word used a .doc extension).

Modern Microsoft Excel documents have a .xlsx filename extension (older versions of Excel used a .xls extension).

When you double click on a file, that file is often opened inside a particular program. Most modern operating systems use the filename extension to determine which program to use with the file. For example files that end with .xlsx are typically automatically opened up in Excel and files that end with .docx are typically automatically opened up in Microsoft Word.

Opening a file with the wrong program usually leads to problems. For example, if you try to open an Excel file with Microsoft Word or a Word file with Excel, the program that you opened will not be able to use the file correctly.

2.2.3 Some files can be opened with different programs.

You typically would open a .docx file with Microsoft Windows. However, other programs exist that can also be used to open a .docx file. For example these other programs can also work with .docx files:

  • LibreOffice Writer - Open-source software that can edit .docx files.

  • WPS Office Writer - A lightweight alternative with .docx compatibility.

  • Apple Pages - Supports .docx on macOS and iOS.

  • OnlyOffice - Free and online office suite for .docx editing.

  • Zoho Writer - Cloud-based editor with .docx support.

  • SoftMaker FreeOffice - Free software supporting .docx files.

If you have more than one of these programs installed on your computer, one of them will be the “default” program to open when you double click on a .docx file. Both Mac and Windows computers have a way to configure which is the default program for each filename extension. The specifics of how to do so often change with different releases of an operating system. For info about how to do so on your computer, please search online with your favorite search engine or AI.

2.2.4 How come I can’t see filename extensions

Changing a filename extension can cause the computer to open up the wrong program when you double click on the filename. Many non-technical users are not aware of this and might inadvertantly change the filename extension without understanding the ramifications. For this reason, on new Windows and Mac computers, the filename extensions are usually hidden from view. The filename extensions exist, they are just hidden from view. There is always a way to show (or hide) the filename extensions. However, different versions of Windows and Mac OS provide different ways to do this.

Search online for instructions on how to either show or hide filename extensions on your computer.

2.3 ZIP files

A ZIP file is a single file that contains multiple files.

2.3.1 How to create a ZIP file?

Search online for info for your operating system.
For example “how can I create a ZIP file from a specific folder on Windows 11”

2.3.2 How to “unzip”, i.e. extract the files, from a ZIP file?

Search online for info for your operating system.
For example “how can I unzip a zip file on Mac Sequoia”.