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Firefox includes a built-in PDF viewer to display PDF files inside the browser window. This article explains how to use the built-in PDF viewer, how to fix the common issues you might encounter, and how to use another PDF viewer.
Table of Contents
- 1 Use Firefox’s built-in PDF Viewer
- 1.1 Fill out forms in PDF Viewer
- 1.2 PDF Viewer toolbar functions
- 1.3 Annotate PDF files
- 1.4 Highlight in PDF files
- 1.4.1 Add a highlight
- 1.4.2 Show/hide all highlights
- 1.4.3 Edit or delete a highlight
- 1.5 Add an image to PDF files
- 1.6 PDF Viewer keyboard shortcuts
- 2 Use a different PDF viewer for downloaded PDF files
- 3 Choose another PDF viewer to use by default or set Firefox to always ask
- 3.1 Disable the built-in PDF viewer and use another viewer
- 3.2 Set Firefox to ask you what to do with PDF files
- 4 Troubleshoot problems with the PDF viewer
Firefox's built-in PDF viewer allows you to view almost all PDF files found on the web without an external application (exceptions to this are PDF files with a MIME type incorrectly set). The built-in viewer is used when Portable Document Format (PDF) files are set to Open in Firefox in your Firefox settings for different types of files. This is the default setting. When you click a link to a PDF file or open it from the Firefox Downloads panel, it will be rendered with the built-in PDF viewer. (To learn more about the built-in viewer, see below.)
The built-in PDF viewer will open the PDF file in Firefox without saving it.
When you're viewing a PDF file in Firefox, you can use the download button in the PDF viewer's toolbar to download and save the PDF file to your computer.
Fill out forms in PDF Viewer
Some PDF files have interactive fields to fill in data (such as on forms). Using Firefox's built-in PDF viewer, you can fill out fields such as text, check boxes and radio buttons. After entering data into these fields, you can download the file to have the filled-out version saved to your computer.
- View document thumbnails or outline: The slider button on the far left will open a sidebar with thumbnails of the document's pages. Some documents will also have an outline view available. These make it easy to navigate through a long document.
- Page up and down or skip directly to a page: You can use the up and down arrows to page through a document or enter the number of the page you want to go to.
- Change the size of the document: Use the + and − buttons to zoom in and out or choose a zoom setting from the dropdown menu.
- Fullscreen or Presentation mode: Click the Presentation Mode button to allow the PDF file to take over your entire screen. Press Esc to exit fullscreen mode.
- Print: Click the Printer button to open the print setup dialog.
- Download: Click the Download button to save the PDF file to your computer.
- Copy current view: Right-clickHold down the control key while you click the current view button to open the current view in another tab or window.
- Print: Click the Printer button to open the print setup dialog.
- Download: Click the Download button to save the PDF file to your computer.
Annotate PDF files
Annotating a PDF allows you to add notes, highlights, and other markings directly on the document. This is especially useful for making corrections, highlighting important information, or adding personal notes for future reference.
- Click
to choose a color and text size before selecting where on the document you wish to add text. - Click to choose a color, thickness and opacity before then being able to draw on the document. Downloading the file saves a copy of the document with your annotations.
Highlight in PDF files
Add a highlight
- To highlight text or an area in a PDF document, first select the desired text or area. Then, click on .
- Choose your preferred highlight color and adjust the thickness of the highlight.
Show/hide all highlights
- To manage the visibility of all highlights in a PDF file,first click at the top right of your screen.
- Then, use the toggle located under the Show all option to either display or hide all the highlights in the PDF file.
Edit or delete a highlight
- Click on the area you previously highlighted.
- To change the color of your highlight, click on and select a new color.
- To remove the highlight, click .
Add an image to PDF files
Starting in Firefox version 119, you will be able to add an image to a PDF file. This feature is being rolled out gradually, so it may not be available to you at this time.
In many PDF-related tasks, incorporating images can provide supplementary information to your content.
Inserting an image:
- On the top right of the screen, click .
- Click + Add image. This will prompt the file selection window.
- Browse and select the desired image file to add it to the PDF.
Repositioning and resizing the image:
- Drag and drop the image to your preferred location within the PDF.
- To adjust the image size, click and drag its borders until it fits your desired dimensions.
Adding Alt Text for accessibility:
- After adding the image, click + Alt text.
- In the provided space, either:
- Write a concise description of the image for screen readers, or
- Mark the image as decorative if it's for aesthetic purposes only.
- Click Save to insert the alt text.
PDF Viewer keyboard shortcuts
| Command | Shortcut |
|---|---|
| Next page | N or J or → |
| Previous page | P or K or ← |
| Zoom in | Ctrl + +Command + + |
| Zoom out | Ctrl + −Command + − |
| Automatic Zoom | Ctrl + 0Command + 0 |
| Rotate the document clockwise | R |
| Rotate counterclockwise | Shift + R |
| Switch to Presentation Mode | Ctrl + Alt + PCommand + Alt + P |
| Choose Text Selection Tool | S |
| Choose Hand Tool | H |
| Focus the Page Number input box | Ctrl + Alt + GCommand + Alt + G |
When Firefox is set as the default PDF viewer, and you download a PDF file in Firefox and save it to your computer, you can use a different application to view those PDF files by following these steps:
- Open the Downloads panel by clicking the download icon next to the address bar. (Alternatively, open the Downloads Library window.)
- Right-clickHold down the control key while you click the download entry for the PDF file you want to open.
- Click the context menu item for the system default PDF viewer (for example, click Open in Adobe Acrobat Reader DC) (for example, click Open in Preview) to open the PDF file in that application.
Note: If you want to view a downloaded PDF file in another application, open the Downloads panel or Library window as explained above, but click the file folder icon for the PDF file entry. This will open the folder containing the downloaded file.click the magnifying glass icon for the PDF file entry. This will open the folder containing the downloaded file in Finder. You can then right-clickcontrol-click the file, select Open with and choose the PDF viewer application you wish to use.
Note: When you choose another PDF viewer to use by default in Firefox, or, if you set Firefox to always ask you what to do with PDF files, any PDF files you open will also be saved to your Downloads folder (see Where to find and manage downloaded files in Firefox).
Disable the built-in PDF viewer and use another viewer
Note: If Firefox is not your current default PDF viewer, you will be prompted to set it as the default when opening a PDF file in Firefox.
You can also set a different third-party PDF viewer to handle PDF files, instead of Firefox’s built-in PDF viewer. To switch from using the built-in PDF viewer to another viewer:
- In the Menu bar at the top of the screen, click Firefox and then select Preferences or Settings, depending on your macOS version.Click the menu button and select Settings.
- In the General panel, go down to the Applications section.
- Find Portable Document Format (PDF) in the list and click the entry to select it.
- Click the arrow under the Action column for the above entry and select the PDF viewer you wish to use from the drop-down menu.
Note: When Open in Firefox is the selected action, the built-in PDF viewer is used.
Set Firefox to ask you what to do with PDF files
If you want Firefox to always ask you what to do with PDF files, follow the above steps to change the action for the Portable Document Format (PDF) entry, except select Always ask from the drop-down menu. The next time you click a link to download a PDF file, Firefox will show you a prompt asking what to do with the file. You can then choose to open it with Firefox's built-in PDF viewer, open it with a different PDF application, or you can choose to save the file.
For more information, see Manage file types and download actions in Firefox.
- With certain types of PDF files, the PDF Viewer may have problems displaying fonts, colors, or the whole document. If some PDF files don't render well or are blank, click the download button on the right side of the document header to open it with the default PDF viewer application on your computer.
- If you can't open any PDF files with the built-in PDF viewer, a Firefox extension could be the cause. You can disable all of your extensions, to see if one of them was the problem. For details, see Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems.
These fine people helped write this article:
AliceWyman, Chris Ilias, philipp, cor-el, Underpass, Thomas, Tonnes, Aleksej, Jesant13, Michael Verdi, scoobidiver, Swarnava Sengupta, ideato, Matt_G, Mozinet, mgatkin, Nybble, Lan, scootergrisen, Artist, Paul, YD, Hopeless Host, Jeff, Angela Lazar, Pascal Chevrel, PGGWriter, Bithiah, Denys, Andrew, Lucas Siebert
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