PDF Software Explained: Readers and Editors

PDF software is a set of tools that view, edit, create, and convert Portable Document Format files. This article defines what PDF software does, explains what a PDF is, separates PDF readers from editors and converters, lists the common tasks such as annotation, merging, signing, OCR, and compression, and names the major PDF tools available. The Portable Document Format, created by Adobe, preserves the layout, fonts, and images of a document so the file appears the same on every device and operating system.

PDF software divides into three roles: a PDF reader displays and prints a file, a PDF editor changes the content, and a PDF converter changes the file format. The sections below cover the definition of PDF software, the format itself, the difference between viewing and editing, the common tasks PDF tools perform, the major tools from Adobe Acrobat to free readers and browser PDF viewers, and the difference between free and paid capabilities. A comparison table sets the three tool types against the tasks each one handles.

What Is PDF Software?

PDF software is a program that views, edits, creates, or converts Portable Document Format files. PDF software opens a PDF for reading, changes the text and images inside, builds a new PDF from another file, or exports a PDF to a different format. PDF software falls into three roles by what each tool does to the file.

• PDF readers display and print files. A PDF reader such as Adobe Acrobat Reader opens a PDF for viewing, annotation, and printing without changing the content.
• PDF editors change the content. A PDF editor such as Adobe Acrobat Pro edits text, images, and pages inside the file.
• PDF converters change the format. A PDF converter exports a PDF to Word, Excel, or an image, or builds a PDF from those formats.

PDF software belongs to the productivity category described in the guide to software applications. A PDF reader ships in most web browsers and operating systems at no cost, while a full PDF editor is usually a paid program.

What Is a PDF?

A PDF is a file format created by Adobe that preserves the layout, fonts, and images of a document across devices. The Portable Document Format stores a fixed representation of a page so the file looks the same on Windows, macOS, and mobile devices. Adobe Systems introduced the PDF in 1993, and the International Organization for Standardization published it as the open standard ISO 32000 in 2008.

A PDF holds several types of content in one file.

• Text retains its exact position. A PDF fixes each line of text in place so the layout does not shift between devices.
• Fonts embed in the file. A PDF embeds fonts so the document displays correctly even when the device lacks the font.
• Images and vectors stay in place. A PDF stores raster images and vector graphics at their set positions and resolutions.
• Forms and signatures attach to the page. A PDF holds fillable form fields and digital signatures within the document.

The fixed layout of a PDF differs from an editable document such as a Word file, which reflows text to fit the screen. The Word format belongs to the productivity package compared in Microsoft Office versus Google Workspace.

What Is the Difference Between Viewing and Editing a PDF?

The difference between viewing and editing a PDF is that viewing displays the file unchanged, while editing alters the content inside the file. A PDF reader opens and shows a file, while a PDF editor changes the text, images, and page order.

• Viewing displays the file as written. A PDF reader renders the page, allows zoom and search, and prints the document without altering the content.
• Annotating adds notes over the content. A PDF reader with markup tools adds highlights, comments, and drawings on top of the page without changing the original text.
• Editing changes the content itself. A PDF editor modifies the text, replaces images, reorders pages, and edits form fields inside the file.

Annotation sits between viewing and editing, since a comment overlays the page without altering the underlying text. Most free PDF readers allow viewing and annotation, while full content editing requires a paid editor.

How Does PDF Software Create a PDF?

PDF software creates a PDF in three ways: printing to PDF, exporting from another program, or scanning a paper document. Each method produces a Portable Document Format file from a different source. The methods below are ordered by how often each one creates a PDF.

1. Print to PDF from any program. A virtual PDF printer, built into Windows and macOS, captures the output of any application as a PDF instead of sending it to paper.
2. Export to PDF from a document. A program such as Microsoft Word or Google Docs exports the open document directly to a PDF through a save or export command.
3. Scan a paper document to PDF. A document scanner captures a paper page as an image and saves it as a PDF, which OCR then converts to searchable text.

A PDF created by printing or exporting holds selectable text from the start, while a scanned PDF holds an image until OCR adds a text layer. Microsoft Word and Google Docs both export to PDF directly, a feature compared in Microsoft Office versus Google Workspace.

What Tasks Does PDF Software Perform?

PDF software performs tasks beyond viewing, including annotation, merging, signing, OCR, and compression. The tasks below are ordered by how often a PDF tool performs each one.

• Annotate marks up a document. Annotation adds highlights, comments, and drawings over a PDF without changing the underlying text.
• Merge combines several PDFs. A merge tool joins multiple PDF files into one document in a set page order.
• Sign adds a signature to a form. An electronic signature applies a typed, drawn, or digital signature to a PDF form or contract.
• OCR converts scanned text to selectable text. Optical Character Recognition reads text inside a scanned image and makes the text searchable and selectable.
• Compress reduces the file size. Compression lowers the size of a PDF by downsampling images, which eases email and upload.
• Split separates pages into files. A split tool extracts pages from a PDF into separate documents.

OCR turns a scanned page into searchable text, which a document scanner produces as an image. A digital signature on a PDF relies on encryption to verify the signer, the same technology covered in the explanation of encryption software.

What Are the Major PDF Tools?

There are 4 categories of PDF tools: Adobe Acrobat, free dedicated readers, browser PDF viewers, and third-party editors. Each category covers a different range of tasks. The tools below are described by the role each one fills.

Adobe Acrobat

Adobe Acrobat is the reference PDF software from the format creator. Adobe Acrobat Reader views, annotates, and signs PDFs at no cost, while Adobe Acrobat Pro adds full content editing, conversion, and OCR as a paid product.

Free Dedicated Readers

Free dedicated readers view, annotate, and print PDFs without a paid license. Programs in this group open and mark up PDFs, fill forms, and print, though they limit deep content editing.

Browser PDF Viewers

Browser PDF viewers open a PDF inside a web browser without separate software. Google Chrome, Microsoft Edge, Mozilla Firefox, and Apple Safari each include a built-in PDF viewer that displays, prints, and annotates a file. The built-in viewer is part of the browser described in the explanation of a web browser.

Third-Party Editors

Third-party editors provide content editing and conversion as Acrobat alternatives. These programs edit text, merge and split files, run OCR, and convert formats, often at a lower cost than Adobe Acrobat Pro.

Free vs Paid PDF Software: What Is the Difference?

The difference between free and paid PDF software is that free tools view and annotate, while paid tools edit content and convert formats. The table below sets the three tool types against the tasks each one handles.

A free PDF reader covers viewing, annotation, signing, and printing for most users. A paid PDF editor adds content editing, format conversion, and OCR for documents that require changes inside the file.

Key Takeaways

• PDF software views, edits, and converts PDFs. PDF software handles the Portable Document Format across three roles.
• A PDF preserves layout across devices. Adobe created the PDF to fix fonts, images, and text positions in one file.
• Readers view, editors change content. A PDF reader displays a file, while a PDF editor alters the text and pages.
• Common tasks include OCR and merging. PDF tools annotate, merge, sign, run OCR, and compress files.
• Adobe Acrobat is the reference tool. Acrobat Reader is free, while Acrobat Pro adds paid editing and conversion.
• Free tools view, paid tools edit. Free readers and browsers view and annotate, while paid editors change content.

Last Thoughts on PDF Software

PDF software views, edits, creates, and converts Portable Document Format files across three roles, since a PDF reader displays a file, a PDF editor changes the content, and a PDF converter changes the format. The Portable Document Format, created by Adobe and standardized as ISO 32000, fixes the layout, fonts, and images so a document appears the same on every device.

Free readers and browser viewers cover viewing, annotation, and signing for most users, while a paid editor such as Adobe Acrobat Pro adds content editing, OCR, and format conversion. PDF software sits within the wider set of software applications, alongside the note-taking apps that capture and store reference material.