PDF技巧、指南和教程
在浏览器中免费转换、压缩、保护、签署、编辑和总结PDF的实用指南。
19 篇文章 · 更新于 2026 年 9 月
全部指南
18 篇文章16 Free Online PDF Tools and When to Use Each One
From merging and compressing to OCR and watermarking — a practical guide to every PDF tool on YumPDF, with tips on picking the right one for your task.
How to Scan Documents to PDF Using Just Your Browser
No app, no scanner hardware needed. Learn how to use your phone or laptop camera to scan receipts, contracts, and handwritten notes directly into a PDF.
How to Compress a PDF Without Losing Quality
Reduce PDF file size by up to 95% for free — understand compression levels, keep quality high, and send any file via email without hitting attachment limits.
How to Merge PDF Files Online — Free, Fast & Private
Combine contracts, reports, and appendices into one clean PDF document in seconds — no software, no sign-up, your files never leave your browser.
How to Split a PDF into Separate Pages or Sections
Extract exactly the pages you need from any PDF document — by range, one per file, or in fixed chunks. Free, private, and done in your browser.
OCR PDF: How to Make Scanned Documents Searchable
Turn image-based and scanned PDFs into real, searchable, copyable text. Free, browser-based, and supports 100+ languages including Hindi and Tamil.
How to Convert PDF to JPG — Free, No Upload Required
Export any PDF page as a high-quality JPG image — choose resolution, convert one page or all, download instantly. No account, no watermark.
How to Convert JPG Images to PDF — Complete Free Guide
Combine one or multiple JPG, PNG, or WebP images into a single professional PDF. Reorder pages, adjust settings, download instantly.
How to Password-Protect a PDF for Free
Add AES-256 encryption to any PDF before sharing contracts, financial records, or personal documents. Free, private, no files uploaded anywhere.
How to Remove a Password from a PDF — Free & Instant
Remove PDF password protection from documents you own. Authenticate with the current password, strip the lock, download the unlocked file — all in your browser.
How to Add a Watermark to a PDF — Free, Browser-Based
Add text or logo watermarks to any PDF document. Set opacity, angle, and position to brand reports, mark drafts, or protect intellectual property.
How to Rotate PDF Pages — Fix Orientation in Seconds
Fix sideways or upside-down PDF pages in three clicks. Rotate individual pages or the full document — free, lossless, and instant in your browser.
How to Add Page Numbers to a PDF — Free Online Tool
Number any PDF document in 30 seconds. Choose Arabic, Roman, or alphabetical format, set position and starting number — no account needed.
How to Compare Two PDF Files and Find the Differences
Instantly highlight every change between two PDF versions — additions, deletions, and modifications. Essential for contracts, policy updates, and legal documents.
How to Edit a PDF Online — Free, No Watermark
Add text, annotations, highlights, and images to any PDF for free. Understand what free editing can and can't do, and when to convert to Word instead.
PDF Privacy: Why You Should Never Upload Sensitive PDFs to Online Tools
Most free PDF tools upload your files to remote servers. Learn what really happens to your documents — and how browser-based tools keep your data completely private.
10 PDF Tricks Every Student Should Know (All Free)
Compress assignments before submission, OCR your handwritten notes, merge dissertation chapters, and more — the complete free PDF toolkit for students.
PDF Tools for Small Business: Handle Documents Without Adobe
Handle invoices, contracts, proposals, and onboarding documents without a $239/year Adobe subscription. A complete small business PDF workflow using free tools.
准备好处理您的PDF了吗？
所有工具都是免费、私密且在浏览器中运行——无需上传，也无需账户。