Mac User Guide
- Welcome
- What’s new in macOS Tahoe
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- Intro to Apple Intelligence
- Translate messages and calls
- Create original images with Image Playground
- Create your own emoji with Genmoji
- Use Apple Intelligence with Siri
- Find the right words with Writing Tools
- Summarize notifications and reduce interruptions
- Use ChatGPT with Apple Intelligence
- Apple Intelligence and privacy
- Block access to Apple Intelligence features
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- Intro to Continuity
- Use AirDrop to send items to nearby devices
- Hand off tasks between devices
- Control your iPhone from your Mac
- Copy and paste between devices
- Stream video and audio with AirPlay
- Make and receive calls and text messages on your Mac
- Use your iPhone internet connection with your Mac
- Share your Wi-Fi password with another device
- Use iPhone as a webcam
- Insert sketches, photos, and scans from iPhone or iPad
- Unlock your Mac with Apple Watch
- Use your iPad as a second display
- Use one keyboard and mouse to control Mac and iPad
- Sync music, books, and more between devices
- Resources for your Mac
- Resources for your Apple devices
- Copyright and trademarks
Show or hide filename extensions on Mac
A filename extension appears at the end of some filenames, and looks like a period followed by a few letters or words (for example, .jpg). A file’s filename extension shows what type of file it is and what apps can open it.
Filename extensions are usually hidden in macOS, but if you find them useful, you can show them. If extensions are hidden, macOS still opens files with the proper apps.
For one file
On your Mac, select a file, then choose File > Get Info, or press Command-I.
Click
next to Name & Extension to expand the section.To show or hide the filename extension, select or deselect “Hide extension.”
For all files
In the Finder
on your Mac, choose Finder > Settings, then click Advanced.Select or deselect “Show all filename extensions.”
If you select “Show all filename extensions,” all extensions are shown, even for files that have “Hide extension” selected. If you deselect “Show all filename extensions,” then file extensions are shown or hidden based on their individual “Hide extension” settings.
When you rename a file or folder, don’t change its filename extension, or you may no longer be able to open the file with the app that was used to create it. To be warned before you change an extension, select “Show warning before changing an extension” in the Advanced pane of Finder settings.
If you want to change a file’s format, use the app you used to create the file. For example, TextEdit can convert a document from plain text format (.txt) to a rich text format (.rtf), and Preview can convert many types of graphics files.