How to Check Whether a File Is a PDF on a Mac

What you need: A Mac, the file you want to check, and the name of the folder it is in, such as Downloads or Documents.

Steps

1. Click Finder (the blue smiling face) in the Dock, the row of app icons along the edge of the screen.
2. In the menu bar at the top of the screen, click Go, then the folder containing your file, such as Downloads or Documents. To open a folder inside it, click that folder twice quickly. Continue until you see your file.
3. Click your file's name once. Its name is highlighted.
4. In the menu bar at the top of the screen, click File, then Get Info. A window with information about the file opens.
5. In that window, find Name & Extension. If there is no box with the file's name below it, click the small arrow beside Name & Extension. The box shows the file's whole name, including its ending.
6. Read the end of the name in that box. If it ends with .pdf, the file is a PDF document. If it ends with something else, such as .html or .docx, it is not a PDF.
7. Leave the name in the box as it is. Typing a new ending, such as changing .html to .pdf, does not turn the file into a different kind of document. If a message asks whether you are sure you want to change the extension, click the button that begins with Keep, such as Keep .html.
8. Click the red button at the upper-left corner of the information window to close it.

Expected result: You saw the whole name of your file, including its ending. A name ending in .pdf is a PDF document.