PDF guides
Each guide answers one question about PDFs with numbers from our own tests, then points to the free tool that fixes the problem in your browser.
Organize PDF
- How to Prepare PDFs for a Job Application
Format, one file or several, size limits, file names and checks, with a real pack measured.
Convert to PDF
- Why a Converted Document Looks Different
Fonts and line spacing measured in 11 fonts: why lines and pages move, and how to stop it. - How to Scan a Document on iPhone and Android
Free built-in scanning on iPhone and Android, and how far a phone scan shrinks. - How to Save a Webpage as a PDF
Browser steps for Chrome, Edge, Firefox and Safari, and why printing beats a screenshot. - HEIC vs JPG
Why iPhone photos fail to upload or open, tested in Chrome, and how to convert them free. - PDF vs JPG: Which Should You Send?
Text, multi-page documents and photos saved both ways: sizes, sharpness and search compared.
Convert from PDF
- Searchable vs Scanned PDF
One invoice as text, as a scan and after OCR: how to tell which you have, and how to fix a scan. - PDF vs DOCX: Which Should You Send?
The same report as both: size, layout, editing and hidden comments compared.
Edit PDF
- Electronic vs Digital Signature
What each kind of signature proves, tested on a signed PDF, and what US and EU law say. - How to Fill Out a PDF on iPhone
Fill, sign and lock a PDF form in Safari, typing in full-size boxes instead of tiny ones.
PDF security
- Why Black Boxes Don't Redact a PDF
A number hidden six ways, found again in five, plus real court and agency failures. - PDF Open Password vs Permissions Password
One file locked both ways: what each password stopped, and which one keeps a PDF private. - What PDF Metadata Reveals About You
Eight hidden details in one memo, from your time zone to an old title, and how to remove them. - Is It Safe to Upload a PDF Online?
What the FBI warned about free converters, and a one-minute test that shows if a tool uploads your file.
Optimize PDF
- Why Is My PDF So Large?
What takes up the space in a PDF, measured, and how to fix each cause. - Email Attachment Size Limits for PDFs
Each provider's limit from its own help page, and why a PDF grows 37% inside an email. - PDF Compression Test
Five kinds of PDF at every compression level: size saved and whether text stays readable, with CSV data. - PDF Too Large to Upload?
Real scans pushed toward 5 MB to 100 KB limits: what fits, and what to do when compression is not enough. - How to Compress a PDF on iPhone
Shrink a PDF in Safari with no app or upload; a 7.8 MB scan came down to 559 KB.