PDF Guides
Practical answers to common PDF questions, each linked to the working tool that solves it.
Ten PDF Claims We Measured Instead of Repeating Them
Zip your PDF to shrink it. Crop it to save space. Common advice that turns out to be wrong when you measure it — with the numbers, and the method to check them.
What Is PDF/A, and Does Your Document Actually Need It?
PDF/A is an ordinary PDF with things forbidden rather than added. What it guarantees, when it is genuinely required, and why most documents should not be one.
Why Is My Scanned PDF Blurry, and Can It Be Fixed?
There are two kinds of blurry scan: one was captured badly, and one was made blurry afterwards. Only one of them can be repaired — here is how to tell which.
PDF Too Large to Email? Work Out Which Fix You Need
Your 24 MB file fails a 25 MB limit, and zipping saves nothing. Here is why, and the five routes to getting a document delivered — only one is compression.
What Hidden Data Your PDF Carries When You Send It
A PDF carries more than its pages: your name, your software, edit history, and sometimes the location a photo was taken. Here is how to find it and remove it.
Why a PDF Form Won't Save the Answers You Typed In
You filled the form, closed it, and reopened an empty one. Work out which of the four causes you have — and the single workaround that survives every reader.
How to Scan and File Paper Records So You Can Find Them
Digitising a box of paper is mostly not scanning. Here is the order of operations that produces an archive you can search, and the settings that decide it.
Why a PDF Looks Different on Someone Else's Computer
PDF promises the same page everywhere and usually delivers. When it does not, the cause is nearly always fonts — and the reason is stranger than you expect.
Why Won't My PDF Print Correctly? Seven Real Causes
The page on screen and the page from the printer disagree. Work out which of the seven causes you have, because the fix for each one is completely different.
Browser PDF Tools vs Desktop Software: What Actually Differs
Both edit PDFs and both produce valid files. The real differences are where your document goes, what limits you hit, and which suits the job in front of you.
How to Add a Watermark to a PDF: Draft or Confidential
Stamp DRAFT, CONFIDENTIAL, or your own logo across a PDF with control over opacity, rotation, and pages — and learn what a watermark cannot protect you from.
How to Add Page Numbers to a PDF in Header or Footer
Number a PDF in the header or footer, use a "Page 1 of 10" format, start from any number, and skip a cover page — without uploading the document to any server.
How to Add Text to a PDF Without Word or Adobe Acrobat
Fill in a PDF form that has no fields, add dates and checkmarks, and place text anywhere — and understand why this is not the same as editing existing text.
How to Prepare a PDF Bundle for Court or Tender Submission
Combining several documents into one submission bundle has a correct order of operations. Get it wrong and the whole thing has to be rebuilt from the start.
How to Reorder PDF Pages Without Uploading the File
Drag PDF pages into the right order, duplicate or delete them, insert blank pages, and fix a duplex scan that came out interleaved — all inside your browser.
How to Rotate PDF Pages Permanently and Save the Fix
Fix sideways or upside-down PDF pages by 90, 180, or 270 degrees and export a corrected file, so the rotation is saved in the document instead of resetting.
Why Can't I Copy Text From a PDF? Two Causes, Two Fixes
Selecting text in a PDF does nothing, or copying is blocked. There are only two real causes — here is how to tell them apart and what genuinely fixes each one.
Why Is My PDF So Large? The Causes and the Real Fixes
A four-page scan can outweigh a forty-page report. Find out which kind of large you have, what actually shrinks it, and when compressing makes things worse.
Why Won't My PDF Open? How to Diagnose and Fix the File
A PDF that refuses to open has a short list of likely causes. Work through them in order — most take seconds, and the file itself is usually fine after all.
How Browser-Based PDF Tools Protect Privacy, Verifiably
Every PDF site promises your files are safe. Here is the structural difference between a promise and an enforced guarantee, and how to check which you have.
Electronic Signature vs Digital Signature: The Difference
One is a picture of your name. The other is a mathematical seal. They get used interchangeably, they are not the same thing, and the gap matters if challenged.
How OCR Makes a Scanned PDF Searchable, Start to Finish
Recognition adds an invisible text layer under the picture, leaving the page looking identical. What that means in practice, and the accuracy you should expect.
Why a PDF Is Not Searchable, and the Four Real Causes
Ctrl+F finding nothing usually means a scan, but not always — a PDF full of real text can fail to search too. Work out which cause you have, then fix that one.
How to Unlock a PDF When You Already Know the Password
Turn a password-protected PDF into an ordinary one using the password you have. What this does, why no honest tool can help without it, and when not to bother.
How to Password-Protect a PDF, and What It Really Protects
A password on a PDF stops it being opened. It does not control what happens next — here is what encryption covers, what it does not, and how to set one well.
How to Sign a PDF Online Without Uploading the Document
Draw, type, or upload a signature and place it on the page, entirely in your browser. What that signature is, what it is worth, and where it is not enough.
How to Crop PDF Margins, and What Cropping Never Does
Cropping changes which part of a page is shown. It does not delete what falls outside, and it will not shrink your file — here is what it actually changes.
How to Remove Pages From a PDF Without Losing the Rest
Deleting pages and keeping pages are the same job asked from opposite ends. Work out which one you have, then remove pages without breaking the pages you keep.
How to Extract Specific Pages From a PDF Into a New File
Send someone the three pages they need instead of the whole forty-page report. How to pull exact pages out, and why extracting usually beats deleting the rest.
How to Split a PDF Into Separate Files the Right Way
Splitting, extracting, and deleting all make a PDF smaller and they are not the same job. Pick the right one, then divide a document without losing anything.
How to Merge PDF Files Without Uploading Them Anywhere
Combining PDFs in your browser keeps them off other people's servers. Here is how to do it, and exactly what survives a merge and what quietly does not survive.
How we write and review these guidesSubscribe to the guides RSS feed