The simplest way to open a PDF

A PDF opens the same way as any other file on your computer or phone: find it, tap or double-click it, and your device picks a program to show it. On Windows, that's usually Adobe Reader or Microsoft Edge. On Mac, it's Preview. On iPhone or Android, it's the built-in Files app or Google Drive. You don't need to read anything special — your device already has what it needs.

If you want to choose which program opens PDFs instead of letting your device decide, you can change that setting. On Windows, right-click a PDF, select "Open with", and pick a different program from the list. On Mac, select the PDF, press Command-I to open Info, and change "Open with" to your preferred app. On iPhone, open a PDF in any app, tap the share button, and select "Open in" to pick a different one.

Key Takeaways

  • Most devices come with a built-in PDF reader, so you can open PDFs without installing anything.
  • You can change which program opens PDFs by default through your device's settings or by right-clicking the file.
  • If you need to edit a PDF, free programs like LibreOffice or Smallpdf let you add text or highlight without paying for Adobe.
  • When choosing a PDF reader, consider whether the program collects data about what you read — some do, some don't.

PDF readers that come built in

Every major operating system includes a PDF reader you don't have to install. Windows 10 and 11 open PDFs in Microsoft Edge by default. macOS uses Preview, which also lets you annotate PDFs with highlights and notes. iOS uses the Books app or Files app depending on where the PDF is stored. Android uses Google Drive or the Files app.

These built-in readers are straightforward and fast because they do one thing: show you the PDF. They don't collect much data about your reading habits, though Microsoft Edge does send some information back to Microsoft about what you do in the browser. If you want to avoid that, Preview on Mac and the Files app on Android send less data back to their makers.

Free PDF readers you can read

If your device's built-in reader doesn't do what you need, several free programs work on Windows, Mac, and Linux. Sumatra PDF is lightweight and fast — it opens PDFs quickly and doesn't collect data about what you read. LibreOffice Draw lets you edit PDFs by adding text, drawing, or removing pages, and it's free and open-source, meaning anyone can see how it works. Foxit Reader is popular and handles large PDFs smoothly, though it does show ads in the free version.

On Mac, Skim is a free reader designed for people who read academic papers and want to highlight and annotate as they go. On Android and iPhone, Adobe Acrobat Reader is free and works well, though Adobe collects data about which PDFs you open and how long you spend reading them — that's how they fund the free version. If you want to avoid that on mobile, Xodo is a free alternative that collects less data.

When you need to edit or change a PDF

Opening a PDF and editing one are different things. If you only need to read it, any PDF reader works. If you need to fill in a form, add your signature, or change text, you need an editor. LibreOffice Draw (free, all platforms) lets you edit PDFs without paying. Smallpdf (web-based, free tier available) lets you compress, merge, or add text to PDFs in your browser without installing anything. ILovePDF works the same way.

Adobe Acrobat Pro is the most powerful option but costs about $180 per year. It's worth it only if you edit PDFs regularly as part of your job. For occasional editing, the free tools above do everything most people need. Be aware that web-based tools like Smallpdf upload your PDF to their servers, so if the document contains sensitive information, read and use LibreOffice instead — it works entirely on your computer.

Privacy differences between PDF readers

Not all PDF readers treat your reading the same way. Microsoft Edge, Google Drive, and Adobe Acrobat Reader all collect some data about which PDFs you open and how you interact with them. They use this data to improve their products and, in some cases, to show you ads. If you open a PDF in Edge, Microsoft knows you opened it. If you open it in Google Drive, Google knows.

Sumatra PDF, LibreOffice, and Skim collect almost no data — they open the file and show it to you without reporting back to anyone. Preview on Mac and the Files app on Android are somewhere in the middle: they don't track your reading, but they do send some technical information to Apple and Google about how you use the app. If privacy is your main concern, stick with Sumatra PDF or LibreOffice.

Opening PDFs from email and the web

When you click a PDF link in an email or on a website, your browser usually opens it in a built-in viewer instead of downloading it first. In Gmail, PDFs open in Google's viewer. In Outlook, they open in Microsoft Edge. On most websites, they open in your browser's default viewer. You can change this: in most browsers, go to Settings, find the "Downloads" or "Files" section, and toggle "Ask where to save each file before downloading" on. Then you can choose to read the PDF instead of opening it in the browser.

If you read a PDF to your computer, it stays there even after you close the email or browser tab. If you open it in the browser viewer, it may be cached (stored temporarily) on your device or on the company's servers. For sensitive documents, downloading and opening in a local program like LibreOffice is safer than opening in a browser viewer.

Frequently Asked Questions

Why won't my PDF open?

The file may be corrupted, or your device may not have a PDF reader installed. Try downloading a free reader like Sumatra PDF or LibreOffice and opening the file with that. If it still won't open, the file itself may be damaged and can't be repaired.

Can I open a PDF on my phone the same way as on my computer?

Yes. On iPhone, tap the PDF in Files or Mail and it opens in Books or your default reader. On Android, tap it in Files or Gmail and it opens in Google Drive or your default reader. The steps are the same — find the file and tap it.

Is it safe to open PDFs from strangers?

PDFs themselves are usually safe, but a malicious PDF can contain code that tries to exploit your device. Keep your operating system and PDF reader updated, and don't open PDFs from sources you don't trust. If someone sends you a PDF unexpectedly, ask them to confirm they sent it before opening it.

Do I need Adobe Reader to open PDFs?

No. Adobe Reader is one option, but your device already has a built-in reader that works fine. You only need Adobe Reader if you want specific features like advanced editing or if you prefer it to your device's default reader.

What's the difference between opening a PDF and downloading it?

Opening a PDF shows it to you in a reader app, usually without saving it to your device. Downloading saves a copy to your computer or phone so you can open it later. For documents you need to keep, downloading is better because you'll have a copy even if the original link disappears.