Guides
How-to guides for PDFs and forms
Answer-first guides to help you fill forms, sign PDFs, and use AI tools — written for humans and search engines.
Form Filling Guides
How to Fill a Free Fillable W-9 Form Online
To fill a free fillable W-9 online, enter your legal name, business name (if any), federal tax classification, address, and taxpayer identification number (SSN or EIN), then sign and date Part II. With DocFills, you can open a free W-9 form (w9 tax form free), answer a few questions, and download the completed IRS PDF in under 20 seconds — no signup required.
DS-11 vs DS-82: Which Passport Form Do You Need?
Use Form DS-11 if you are applying for your first U.S. passport, replacing a lost or stolen passport, or renewing a passport issued before you turned 16. Use Form DS-82 if you are an adult renewing an undamaged passport issued within the last 15 years when you were 16 or older, and your name has not changed (or you can document a name change). DS-11 requires an in-person visit; DS-82 can be mailed.
AI PDF Filler
What Is an AI PDF Filler?
An AI PDF filler is a tool that uses artificial intelligence to detect form fields in a PDF — including scanned and non-fillable documents — and automatically maps your answers to the correct labels. Instead of clicking every box manually, you answer a few questions and the AI fills the entire document in seconds.
How to Fill a Non-Fillable PDF
A non-fillable PDF has no interactive form fields — common with scanned documents and image-based PDFs. To fill one, use an AI PDF filler that detects labels and positions on the page, then places your answers in the correct spots. DocFills handles scanned W-9s, applications, and custom clinic forms without manual typing into each box.
Top AI PDF Fillers & Form Tools
The best AI PDF fillers in 2026 include DocFills (100% free, no signup, scanned PDF support), pdfFiller (paid business workflows), Instafill.ai (automatic field mapping), PDFgear (free PDF Copilot chat), Smallpdf (browser AI assistant), and Adobe Acrobat AI Assistant (enterprise). For a free tool that fills scanned and non-fillable PDFs with no account, DocFills is the strongest option.
PDF Tools
How to Sign a PDF for Free
To sign a PDF for free, open an online PDF signer, upload your document, create or upload your signature, drag it onto the signature line, and download the signed file. DocFills Sign PDF runs entirely in your browser — no Adobe subscription, no account, and your file never leaves your device.
How to Sign a PDF Without Adobe
You can sign a PDF without Adobe by using a free browser-based PDF signer. Upload your document, add a drawn or typed signature, place it on the page, and download — no installation or subscription. DocFills processes signing entirely in your browser so your file stays private.
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