The three ways to edit a PDF on your Mac

You can modify a PDF on your Mac using three different tools, each built into the system or available free. Preview is the fastest for straightforward changes — highlighting text, adding notes, rotating pages, or filling in forms. Apple's PDF Markup (part of Mail and Messages) works when you need to sign documents or add quick annotations. For more complex edits like removing pages, reordering, or changing text itself, you will need a dedicated PDF editor, either free (like PDFtk or open-source options) or paid (like Adobe Acrobat Pro or third-party Mac apps).

The tool you pick depends on what you are actually changing. If you are signing a contract, adding your initials to a form, or highlighting a section for someone else, Preview handles it in seconds. If you need to delete a page, merge two PDFs, or edit the actual text that was printed into the document, you need something more powerful.

Key Takeaways

  • Preview, built into every Mac, can highlight text, add notes, rotate pages, and fill in form fields without any read.
  • To edit text that is already printed in a PDF, you need a dedicated PDF editor because Preview cannot change the words themselves.
  • Signing a PDF or adding your initials takes 30 seconds in Preview using the Markup tools in the toolbar.
  • Removing pages, reordering pages, or merging multiple PDFs requires either a paid editor like Adobe Acrobat Pro or free command-line tools if you are comfortable with Terminal.

Using Preview for annotations and form filling

Open the PDF in Preview by double-clicking it or right-clicking and selecting "Open With" then "Preview". Once the document is open, click the Markup toolbar button (it looks like a toolbox) in the top right of the window. This reveals a row of annotation tools: a pen for drawing, a highlighter, a text box for adding comments, a signature tool, and a shape tool for drawing boxes or circles.

To highlight text, click the highlighter icon, then click and drag across the words you want to mark. To add a typed comment, click the text box icon and click where you want the note to appear, then type. To sign the document, click the signature icon, then choose "Create Signature" if this is your first time — you can draw your signature with the trackpad or use your camera to photograph a handwritten signature. Once you have created it, click where you want it to appear on the PDF.

After you make changes, save the file by pressing Command+S. Preview will ask whether you want to save as a new file or overwrite the original. If you are unsure, choose "Save As" to keep both versions.

Filling in form fields without markup tools

Some PDFs are interactive forms with clickable boxes for text entry, checkboxes, and dropdown menus. Preview recognizes these automatically. When you open the PDF, you can click directly into any text field and type, check boxes by clicking them, or select options from dropdowns — no Markup toolbar needed.

If the form field is not responding to clicks, the PDF may not be a true interactive form. In that case, use the text box tool from Markup (the "A" icon) to type your answer near the blank line. This creates a text annotation rather than filling a form field, but it accomplishes the same thing visually.

Rotating, deleting, or reordering pages in Preview

Preview can rotate individual pages and delete pages you do not need. Open the PDF and click the sidebar icon (three horizontal lines) in the top left to show the page thumbnails. Right-click any page thumbnail and choose "Rotate Left" or "Rotate Right" to turn that page 90 degrees. To delete a page, right-click its thumbnail and select "Delete".

To reorder pages, click and drag a thumbnail to a new position in the sidebar. This is useful when pages have been scanned out of order. After you reorder or delete pages, save the file with Command+S.

Preview cannot merge two separate PDFs into one file. If you need to combine multiple PDFs, you will need a different tool.

Merging PDFs and editing text — when you need a stronger tool

If you need to combine multiple PDF files into one document, or if you need to change the actual text that is printed in the PDF (not just add notes on top of it), Preview is not enough. Editing the text itself requires a tool that can read and modify the PDF's internal structure.

Adobe Acrobat Pro is the industry standard and can do everything — merge files, edit text, delete pages, add pages, and change images. It costs a monthly subscription. PDFtk is free and runs from Terminal; it can merge, split, rotate, and delete pages but cannot edit text visually. Preview combined with a free online tool like iLovePDF or Smallpdf can merge PDFs if you do not want to pay for software, though you will be uploading your files to a third-party server.

For most people, the choice comes down to frequency and complexity. If you merge PDFs once a month, a free online tool is fine. If you do it daily or need to edit text, Adobe Acrobat Pro or a similar paid editor saves time. If you are comfortable with command-line tools, PDFtk is powerful and free.

Exporting your edited PDF in the right format

After you finish editing in Preview, the file stays as a PDF by default when you save it. If you need to convert it to another format — like JPG images, TIFF, or PNG — Preview can do that. Go to File menu, then "Export", and choose the format you want from the "Format" dropdown. This is useful if you need to share individual pages as images or if another program requires a specific file type.

Be aware that exporting to an image format (JPG, PNG, TIFF) converts each page to a separate image file. If your PDF has 10 pages, you will get 10 image files. Exporting to PDF keeps it as a single file.

Troubleshooting common editing problems

If you cannot click into a text field in Preview, the PDF may be a scanned image rather than a true PDF with text. Scanned documents are pictures of pages, not editable text. You can still add annotations on top with the Markup tools, but you cannot fill in the form fields themselves. Some PDFs are also locked by their creator to prevent editing — Preview will tell you this when you try to open them, and you will need the password or a different tool to unlock them.

If your annotations are not saving, make sure you are using "Save" (Command+S) and not just closing the window. Preview will prompt you to save if there are unsaved changes, but it is straightforward to miss the dialog. If you accidentally closed without saving, the changes are lost — Preview does not keep a recovery version.

Frequently Asked Questions

Can I edit the text inside a PDF using Preview?

No. Preview can add notes, highlights, and signatures on top of a PDF, but it cannot change the words that are already printed in the document. To edit text itself, you need Adobe Acrobat Pro or a similar dedicated PDF editor.

How do I sign a PDF on my Mac?

Open the PDF in Preview, click the Markup toolbar button (toolbox icon), then click the signature tool. If you have not created a signature before, choose "Create Signature" and either draw it with your trackpad or photograph a handwritten signature with your camera. Click where you want the signature to appear on the PDF, then save the file.

What is the difference between Preview and Adobe Acrobat Pro?

Preview is free and handles annotations, form filling, page rotation, and deletion. Adobe Acrobat Pro costs monthly and can also edit text, merge PDFs, compress files, and perform advanced tasks. For basic edits and signing, Preview is enough. For frequent or complex work, Acrobat Pro saves time.

Can I merge two PDFs using Preview?

No. Preview can rotate, delete, and reorder pages within a single PDF, but it cannot combine two separate PDF files. Use a free online tool like iLovePDF, or use Adobe Acrobat Pro if you merge files regularly.

Why can't I click into the form fields in my PDF?

The PDF may be a scanned image (a picture of a form) rather than an interactive form with actual text fields. You can still add notes using the Markup text box tool, but you cannot fill in the fields themselves. Some PDFs are also password-protected to prevent editing — Preview will show a lock icon if this is the case.