Opening a PDF file on your computer or phone

A PDF opens in whatever program your device has set as the default. On Windows, that is usually Microsoft Edge or Adobe Acrobat Reader. On Mac, it is Preview. On iPhone or Android, it is the built-in Files app or Google Drive. Double-click or tap the file, and it opens when ready — you do not need to install anything extra.

If the PDF opens in a program you do not like, you can change the default. Right-click the file on Windows, select "Open with", then choose a different program from the list. On Mac, right-click and select "Open With", then pick your preference. On phone, the process varies: Android users can long-press the file and select "Open with" to choose an app; iPhone users can tap and hold, then select "Open".

If you want to open a PDF that is stored online — in an email, on a website, or in cloud storage like Google Drive or OneDrive — you can usually view it directly in your web browser without downloading it first. Right-click the link and select "Open in new tab" to keep your place, or straightforward click it to view the file in the same window.

Key Takeaways

  • PDFs open automatically in your device's default program, and you can change which program opens them by right-clicking and selecting "Open with".
  • You can view PDFs stored online without downloading them by opening the link in your web browser.
  • Basic editing like highlighting, adding notes, and rotating pages works in free programs like Adobe Acrobat Reader and Preview.
  • To make permanent changes to text or images, you need a paid editor like Adobe Acrobat Pro or a free alternative like LibreOffice Draw.
  • Sharing a PDF is as straightforward as emailing the file or uploading it to cloud storage, but password protection prevents others from editing or printing.

Highlighting, annotating, and marking up a PDF

Most free PDF readers let you highlight text, add notes, and draw on the page without changing the original file. In Adobe Acrobat Reader (free version), open the PDF, then click the "Draw" tool in the toolbar to access highlighting, underlining, and note-taking. In Preview on Mac, click the markup toolbar icon (it looks like a pen in a circle) to highlight, underline, or add text boxes and shapes.

These markups are saved to the file itself, so when you close and reopen the PDF, your highlights and notes stay there. If you want to remove a markup, select it and press Delete. Be careful: if you share the marked-up PDF with someone else, they will see all your annotations.

On phone, the process is similar. In Adobe Acrobat Reader on iPhone or Android, tap the markup icon (usually a pen or highlighter) to access the same tools. In Google Drive on either phone, open the PDF and tap the pencil icon to annotate.

Rotating, cropping, and rearranging pages

If a PDF page is sideways or upside down, you can rotate it. In Adobe Acrobat Reader, right-click the page thumbnail on the left side and select "Rotate Clockwise" or "Rotate Counterclockwise". In Preview on Mac, select the page and use the Tools menu to rotate. These changes save to the file.

Cropping a page — cutting away the edges to focus on a specific area — works in Preview and some other free readers. In Preview, select the crop tool from the toolbar, drag to select the area you want to keep, then press Enter. The cropped version saves to the file.

If you need to remove pages entirely or rearrange their order, free readers have limits. Adobe Acrobat Reader (free) lets you delete pages but not reorder them. To reorder pages, you need Adobe Acrobat Pro (paid) or a free alternative like PDFtk or Smallpdf online. Drag pages in the left panel to move them around, then save.

Converting a PDF to another format

You may need to turn a PDF into a Word document, image file, or spreadsheet. The method depends on what the PDF contains and what program you have available.

For a PDF that is mostly text, Microsoft Word can open it directly. On Windows, open Word, go to File > Open, and select the PDF. Word converts it to an editable document, though formatting may shift. On Mac, the process is the same. Google Docs also converts PDFs: upload the file to Google Drive, right-click it, select "Open with" > "Google Docs", and it converts to an editable document you can read as Word format.

For a PDF that is mostly images or scanned pages, you need an image converter. Free online tools like Smallpdf, ILovePDF, or CloudConvert let you upload the PDF and read it as JPG, PNG, or other image formats. For scanned documents with text you want to extract, optical character recognition (OCR) software reads the text and converts it to editable format. Adobe Acrobat Pro includes OCR; free alternatives include Tesseract (command-line tool) or online services like OnlineOCR.

Merging multiple PDFs into one file

If you have several PDFs you want to combine into a single file, free tools make this straightforward. On Mac, Preview can merge files: open the first PDF, then go to File > Insert > Page from File, and select the other PDFs in order. Save the result as a new file.

On Windows or Mac, free online tools like Smallpdf, ILovePDF, or PDFtk let you upload multiple PDFs, arrange them in the order you want, and read the merged result. Drag files into the tool, reorder them if needed, then click Merge or Combine. The process takes seconds.

If you merge files regularly, desktop software like PDFtk (free, command-line) or Adobe Acrobat Pro (paid, graphical interface) may be worth learning. For occasional merging, the online tools are faster and require no installation.

Protecting a PDF with a password

Password protection prevents others from opening, editing, or printing your PDF. The method depends on your program and what level of protection you need.

In Adobe Acrobat Pro, open the PDF, go to File > Properties > Security, and set a password. You can require a password to open the file, or allow opening but prevent editing and printing. In Preview on Mac, go to File > Export as PDF, then click the Security button to set a password. Free online tools like Smallpdf also add password protection: upload the file, set your password, and read the protected version.

Be aware that password protection in free tools is often weaker than in paid software. If security is critical — for legal documents, financial records, or sensitive information — use Adobe Acrobat Pro or a dedicated encryption tool. Store your password somewhere safe; if you forget it, recovery is difficult or impossible.

Sharing a PDF by email or cloud storage

The simplest way to share a PDF is to attach it to an email. Most email programs (Gmail, Outlook, Apple Mail) have an Attach button. Click it, select your PDF file, and send. The recipient downloads the file and opens it in their default PDF reader.

For large files or multiple PDFs, cloud storage is faster and easier. Upload the file to Google Drive, OneDrive, Dropbox, or iCloud Drive, then share the folder or file link. The recipient can view the PDF in their browser without downloading, or read it if they need a local copy. You can set permissions: allow viewing only, or allow editing if you want feedback.

If you want to prevent the recipient from editing, printing, or downloading the file, password-protect the PDF before sharing, or use your cloud storage's permission settings to allow viewing only. Google Drive and OneDrive let you disable downloading and printing on shared files, even without a password.

Frequently Asked Questions

Can I edit text directly in a PDF without special software?

Free PDF readers like Adobe Acrobat Reader and Preview let you add notes and highlight, but not change the original text. To edit text itself, you need Adobe Acrobat Pro or a free alternative like LibreOffice Draw. Some online tools like Smallpdf or ILovePDF also let you edit text in the browser, though the results may not match the original formatting exactly.

What is the difference between rotating a page and cropping it?

Rotating turns the entire page 90, 180, or 270 degrees — useful when a page is sideways. Cropping cuts away the edges to focus on a specific area, removing content permanently. Both changes save to the file in most free readers.

Why does my PDF look different after I convert it to Word?

Word conversion works best for straightforward text documents. Complex layouts, images, columns, and special fonts often shift or disappear because Word and PDF handle formatting differently. For PDFs with precise layouts, converting to an image format (JPG or PNG) preserves the appearance but makes the text non-editable.

Is it safe to use free online PDF tools with sensitive documents?

Free online tools are convenient but upload your file to someone else's server. For sensitive information like financial records or legal documents, use desktop software like Adobe Acrobat Pro or password-protect the file before uploading. Check the tool's privacy policy to see how long files are stored and whether they are deleted automatically.

Can I undo changes I made to a PDF?

Most PDF readers do not have an undo button. Once you save changes like deleting pages or rotating them, they are permanent. Before making major changes, save a copy of the original file with a different name, so you have a backup if something goes wrong.