PDF Guides
Step-by-step guides for everyday PDF jobs, from protecting and compressing files to splitting scans and building fillable forms, plus explainers for formats such as PDF/A. For quick definitions, see the PDF glossary.
What Is PDF/A? The ISO 19005 Standard for Archiving PDFs
PDF/A is the ISO 19005 format for archiving PDFs so they open the same in decades. Learn the versions, the a, b and u levels, the rules and how to validate one.
What Is PDF/X? The ISO 15930 Standard for Print-Ready PDFs
PDF/X is the ISO 15930 family of print-ready PDF standards. See how PDF/X-1a, X-3 and X-4 differ on color, fonts and transparency, plus bleed and output intent.
Tagged PDF and Accessibility: How to Make a PDF Screen Readers Can Use
What a tagged PDF is and how to make PDFs accessible. Covers tags, reading order, alt text, PDF/UA, WCAG 2.1 and Section 508, and testing with screen readers.
How to Redact a PDF Properly (and Permanently)
Black boxes leave text anyone can copy. Learn how to redact a PDF for good by removing text, images, the hidden OCR layer and metadata, then check the result.
How to Flatten a PDF (and When You Should)
Flattening a PDF merges form fields, comments and layers into the page so they can't be edited. See what you lose, when to flatten and how it affects signing.
What Is Bates Numbering? Bates Stamps Explained with Examples
Bates numbers are unique page IDs like ABC000001 stamped on each page of a legal document set. See examples, the prefix and digit format and how stamping works.
Digital vs Electronic Signature: What's the Difference?
Digital vs electronic signature explained. Learn how PKI makes a digital signature different, what ESIGN and eIDAS require, and which to use when signing PDFs.
How to Fill Out a PDF Form (Fillable, Flat or Scanned)
How to fill out a PDF form: click each field, type, then save. Steps for fillable, flat and scanned forms in your browser, Acrobat Reader, Preview or a phone.
PDF Page Sizes in Points, mm and Pixels
PDF page sizes in points, millimetres and pixels for A4, Letter, Legal, A3 and A5 at 72, 150 and 300 DPI, with the formulas to work out any other size.
How to Password Protect a PDF in Adobe Reader (Free and Paid Ways)
Free Adobe Acrobat Reader can't add a PDF password. See how to do it in Acrobat Standard or Pro, and how to do it free in your browser with AES-256.
How to Password Protect a PDF File: 5 Ways, Free and Paid
Password protect a PDF file for free in your browser with AES-256, or in Adobe Acrobat, Mac Preview or Word, and learn open vs permissions passwords.
How to Compress a PDF in Adobe Acrobat and Adobe Reader
Compress a PDF in Adobe Acrobat with Compress a PDF or Reduced size PDF. Why free Adobe Reader can't, what Adobe's online tool allows, and a free alternative.
How to Reduce PDF File Size: Make a PDF Smaller on Any Device
Reduce PDF file size for free. Compress images, hit a set size like 1 MB, use Preview on Mac or Shortcuts on iPhone, go grayscale or remove pages.
How to Convert a PDF to a Google Doc (and Keep the Formatting)
Convert a PDF to a Google Doc by uploading it to Google Drive, right-clicking it and choosing Open with > Google Docs. See what carries over, what is lost and a better route.
How to Save a Google Doc as a PDF on Any Device
Save a Google Doc as a PDF with File > Download > PDF Document (.pdf). Plus print to PDF, Android and iPhone steps, emailing a PDF and fixing page breaks.
How to Convert a PDF to JPG on Any Device
How to convert a PDF to JPG for free on Windows, Mac, iPhone, Android or in Acrobat, plus which DPI to pick and when PNG is better.
How to Convert a Picture to PDF on iPhone
Convert a picture to PDF on iPhone for free with the Photos print trick, Files, the Preview app, Notes scanning or Safari, and combine photos in the order you want.
How to Remove a Password from a PDF (When You Know It)
Remove a password from a PDF you own by opening it with the password and saving an unlocked copy. Steps for PDFToolz, Chrome, Mac Preview and Adobe Acrobat.
How to Split PDF Pages into Separate Files
To split a PDF file by pages, type ranges like 1-3, 4-10 and save each as its own PDF. Steps for PDFToolz, Mac Preview, Chrome and Adobe Acrobat.
Difference Between PDF and Word: Which Format to Use
The difference between PDF and Word is purpose. Word is an editable draft and PDF is a fixed final copy. Compare layout, size, security, signatures and conversion.
What Does PDF Stand For? Portable Document Format Explained
PDF stands for Portable Document Format, the file type Adobe launched in 1993 to show pages the same on any device. Learn its history, versions and types.
How to Create a PDF File from Any Document, Photo or Page
Create a PDF file with Save As, Download as PDF or print to PDF. Steps for Word, Google Docs, photos, scans, text, HTML, phones and fillable forms.
How to Sign a PDF Document Electronically
To sign a PDF electronically, draw, type or upload a signature, place it on the page and save. Free steps for the browser, Mac Preview and Acrobat Reader.
How to Combine Front and Back Scans into One PDF
Combine front and back scans into one PDF for free. Interleave a fronts file and a backs file, fix reversed backs and merge odd and even pages in your browser.
How to Remove Blank Pages from a Scanned PDF
Remove blank pages from a scanned PDF for free. Detect empty and near-empty pages by ink, review the thumbnails and save in your browser. Scanner settings too.
How to Split a PDF by Size for Upload and Email Limits
PDF too large to upload? Split a PDF by size into parts under 10, 18 or 25 MB. See the Gmail, Outlook, USCIS and court e-filing limits, and when to compress instead.
PDF Bookmarks vs Table of Contents: What's the Difference?
PDF bookmarks sit in the reader's side panel and never print. A table of contents is a page in the file. Learn the difference and how to add both for free.
How to Create a Fillable PDF Form for Free
How to create a fillable PDF form from a PDF, Word file or scan. Add text boxes, checkboxes and dropdowns free in your browser, or use Acrobat's Prepare a form.
How to Extract Comments and Attachments from a PDF
How to export comments from a PDF to Excel, Markdown or JSON, and extract embedded files and portfolio attachments. Free browser steps, plus Acrobat's own options.