The three ways to add text to a PDF

You can write in a PDF in three different ways, depending on what the document is and what you need to do. The simplest is using the text tool in your PDF reader — most readers have one built in, and it lets you type new text anywhere on the page. The second is filling form fields, which works only if the PDF was created with interactive boxes for you to complete. The third is annotating — adding comments, highlights, or handwritten notes without changing the original document itself.

Which method you use depends on whether the PDF is a form, whether you want to permanently change it, and what software you already have. A form with blank boxes needs the form-field approach. A scanned image of a document needs annotation or a specialized tool. A regular PDF where you want to add your own text uses the text tool.

Key Takeaways

  • Most PDF readers — including Adobe Reader, Preview on Mac, and free tools like Foxit — have a built-in text tool that lets you type directly onto any PDF page.
  • Form fields are interactive boxes that the PDF creator set up for you to fill in; they work in almost every PDF reader and save your entries when you close the file.
  • Annotation tools let you highlight, underline, and add comments without permanently changing the original PDF, which is useful for review and feedback.
  • Scanned PDFs (images of paper documents) cannot be edited with text tools; you need OCR software to convert them to searchable, editable text first.
  • If you need to edit a PDF heavily or create one from scratch, a dedicated PDF editor like Adobe Acrobat Pro or Affinity Publisher is faster than using a reader's basic tools.

Using the text tool in your PDF reader

Most PDF readers have a text tool that works the same way across different programs. Open your PDF, look for a button labeled "Add Text", "Text Tool", or an "A" icon in the toolbar, and click it. Your cursor will change to a text cursor. Click anywhere on the page where you want to type, and a text box will appear. Type your text, and it will stay in that location on the page.

In Adobe Reader (the free version), click the "Fill & Sign" button in the toolbar on the right, then click "Add Text". In Preview on Mac, go to Tools > Annotate > Text. In Foxit Reader, click the "Comment" tab and select "Text Box". In Google Chrome, open the PDF and click the pencil icon in the toolbar, then select the text tool. The text you add is saved to the PDF file itself, so it will appear the same way when someone else opens it.

You can usually change the font size, color, and font by right-clicking the text box or looking for formatting options in the toolbar. Most readers let you move the text box around by clicking and dragging it, and delete it by selecting it and pressing Delete.

Filling in PDF forms with interactive fields

If a PDF has interactive form fields — blank boxes, checkboxes, or dropdown menus — you can fill them in directly without using a text tool. Click inside any field and type or select an option. The form remembers what you entered. When you save the file, your answers stay in the PDF.

Form fields work in every PDF reader, including the free ones. You do not need special software. straightforward click in a field, type or select your answer, move to the next field, and repeat. If a field has a dropdown menu, click the arrow to see your options. If it is a checkbox, click it to mark it checked or unchecked. When you are done, save the file — your entries will be preserved.

If you cannot click into a field or type in it, the PDF may not have interactive fields set up. In that case, you will need to use the text tool instead, or ask whoever created the form to add interactive fields.

Adding comments and highlights without changing the original

Annotation tools let you mark up a PDF — highlight text, underline, strike through, add comments, or draw — without permanently editing the document. This is useful when you are reviewing someone else's work, giving feedback, or marking a document for yourself without altering the original.

In most readers, look for a "Comment" or "Annotate" button in the toolbar. You will see options for highlighting, underlining, strikethrough, and adding text comments or sticky notes. Click the tool you want, then click or drag on the page to explore it. Your annotations appear as overlays on the PDF. When you save, the annotations are saved with the file, but the original content underneath remains unchanged.

If you send an annotated PDF to someone else, they can see your highlights and comments if they open it in a reader that supports annotations. Some readers, like Adobe Reader, also let you reply to someone else's comments, making it useful for collaborative review.

What to do if your PDF is a scanned image

If your PDF is a scanned image of a paper document or photograph, the text tool will not work — you cannot type into an image the way you can into a text-based PDF. The document looks like text to you, but the PDF reader sees it as a picture.

To make a scanned PDF editable, you need OCR (optical character recognition) software, which reads the image and converts it into actual text. Some PDF readers have OCR built in. Adobe Reader does not, but Adobe Acrobat Pro does. Free alternatives include Tesseract (command-line tool), Free Online OCR (web-based), or Smallpdf (web-based, limited free conversions per month).

After OCR converts the scanned image, you can use the text tool normally. Be aware that OCR is not perfect — it may misread handwriting, unusual fonts, or low-quality scans. Always review the converted text before relying on it.

When to use a dedicated PDF editor instead

If you are making many changes, creating a PDF from scratch, or need precise control over layout and formatting, a dedicated PDF editor is faster than using a reader's basic tools. Adobe Acrobat Pro is the industry standard and handles complex edits, form creation, and batch processing. Affinity Publisher is a one-time purchase alternative that works well for design-heavy PDFs. PDFtk is free and command-line based, useful for merging, splitting, or filling forms in bulk.

For straightforward tasks — adding a signature, filling a form, or typing a few lines of text — your PDF reader's built-in tools are enough. For heavy editing, creating forms, or working with many PDFs at once, an editor saves time and gives you more options.

Saving your changes so they stay in the file

After you add text or fill in a form, save the file to keep your changes. Use Ctrl+S (Windows) or Command+S (Mac), or go to File > Save. Most readers will ask you where to save the file the first time — choose a location you can find later.

If you want to keep the original PDF unchanged and save your edits in a separate file, use File > Save As instead and give it a new name. This way you have both the original and your edited version.

Some readers, like Google Chrome, may not save changes to the original file — they may save to a temporary location instead. If you need the changes to stay permanently, read the PDF to your computer first, edit it there, and save it locally.

Frequently Asked Questions

Can I write in a PDF on my phone or tablet?

Yes. Adobe Reader, Foxit, and Apple Books all have mobile versions with text and annotation tools. Open the PDF, tap the pencil or text icon, and type or annotate the same way you would on a computer. Changes save to the file when you close it.

What if the text tool is grayed out or not working?

The PDF may be locked or protected. Try opening it in a different reader — some readers respect restrictions that others ignore. If it is locked with a password, you will need the password to edit it. If the PDF is a scanned image, use OCR software first.

Can I change the font or size of text I add to a PDF?

Yes, in most readers. Right-click the text box you created and look for formatting options, or check the toolbar for font, size, and color buttons. Some readers have limited font options — if you need specific fonts, a dedicated PDF editor gives you more control.

Will my edits show up if I email the PDF to someone else?

Yes, as long as you saved the changes before sending it. Text you added with the text tool and form fields you filled in will appear in the PDF when they open it. Annotations (highlights, comments) will also show up if their reader supports them.

How do I remove text I added to a PDF?

Click the text box to select it and press Delete. If that does not work, right-click it and look for a "Delete" or "Remove" option. For annotations like highlights, select the highlight and press Delete. Save the file after removing text so the changes stick.