Guides

Turning PDF Pages into Images and Back Again: What You Lose

Round-tripping a PDF through PNG or JPEG - when it helps, and what it costs in text, quality and size

Does Hiding Text in a PDF Remove It? A Test on 2009-Era US Government Documents

Seven ways of hiding one line of text in 200 real PDFs - black boxes, annotations, a rewrite, pictures and Redact - and what could still be recovered

Assembling a PDF Packet: Merge, Organize, Then Number

The order of operations that keeps an application or filing correct - and the step people do too early

What Metadata Do Public PDFs Carry? A Study of 2009-Era US Government Documents

Counts from a fixed, repeatable sample of government PDFs: authors, software, file paths, edit history, hidden content - and what HerePDF's tools left behind

Using HerePDF With No Internet: Proof That Your Files Stay on Your Device

Visit once, switch to airplane mode, and merge a PDF - how to check the privacy claim yourself, and what to expect

Making a Flat PDF Fillable: Add Text Boxes, Check Boxes and Radio Buttons

Turn a scan or flat export into a form people can type into, check it works, and know what these fields cannot do

Before You Send That PDF: A Five-Minute Checklist

What a PDF can still carry after it looks finished - properties, photos, comments and attachments, hidden content, size

Cropping a PDF: What Stays Hidden in the File

Cropping and resizing change what is visible - not what the file contains

Adding Bookmarks to a PDF: Make a Long Document Easy to Navigate

Why a long PDF needs bookmarks, how to add and nest them without uploading, pasting in a table of contents, and what merging, reordering and splitting keep

Comparing Two PDF Versions: Finding What Changed Before You Sign

Comparing the words and comparing the pages as pictures: what each can and cannot see, and how to use both before signing

Putting Double-Sided Scans in Order: Interleave and Reverse

Fronts and backs scanned separately, or fed in reverse - rebuilding the reading order without scanning again

Removing Hidden Data from a PDF: What Stays and What Goes

Comments, attachments, scripts and preview images travel unseen - how to find them, remove them, and what no tool can take out

PDF Too Big to Email? What Works, in Order of Effort

A practical ladder: find out what is big, trim what is safe, split what is left - and where the limits are

Copying Text Out of a PDF: Why It Comes Out Jumbled

Columns interleaved, words split by hyphens, tables flattened - what a PDF text layer actually stores

Turning Photos or Scans into a Single PDF for a Submission

Getting a phone-photographed document accepted by a portal that wants one PDF

PNG or JPEG? Choosing a Format and DPI When Exporting PDF Pages

Which format suits text, which suits photos, and what DPI actually buys you

Merging PDFs: Getting the Page Order Right the First Time

Filename sorting traps, mixed page sizes, and what merging does to bookmarks

PDF Page Sizes Explained: A4, Letter, and Why Your Pages Come Out Wrong

Points, DPI and paper sizes - and what real pages show about Letter, A4 and mixed sizes

How to Fix a Sideways or Upside-Down Scanned PDF

Why rotation sometimes doesn't stick, and how to make it permanent

Password-Protected PDFs: What Browser Tools Can and Can't Do

The two kinds of PDF password, what HerePDF does with each, and why an owner-password file won't edit

Why Hiding Text in a PDF Usually Doesn't Remove It

Black boxes and highlighter tools don't delete anything - what actually redacts a document

Signing a PDF Without Uploading It - and What a Drawn Signature Proves

Drawn, typed or scanned signatures, dates and initials - and what they do and do not prove

Filling In a PDF Form Without Uploading It - and When to Flatten It

Fillable vs flat forms, what flattening does, and what does not carry over

Annotating a PDF Without Uploading It - and What Your Comments Reveal

Highlights and notes as real PDF comments, what the recipient sees, and the name your PDF app signs them with

How to Reorder and Delete PDF Pages Without Uploading Them

Restructure a PDF - reorder, remove, duplicate, and splice in pages - without sending it to a server

Why Your PDF Is So Large - And What Actually Makes It Smaller

What takes up space inside a PDF, and which size-reduction methods genuinely work

Scanned vs Text-Based PDFs: How to Tell, and Why It Changes Everything

A five-second test, and why the answer determines what every PDF tool can do

How to Split a PDF Without Uploading It

Extract pages from a PDF without sending the file to a server

Client-Side vs Upload PDF Tools: What Happens to Your File

What happens to a file you upload, how browser-based tools avoid it, how to check, and a measurement of HerePDF's own merge

Hidden Metadata in PDFs: What Your File Reveals About You

Author names, software, timestamps and edit history travel with the file

Numbering PDF Pages - And Which Ones Not To Count

Cover pages, front-matter Roman numerals, and skipping a page mid-document without breaking the count

Watermarking a PDF - And What It Doesn't Protect You From

What a watermark is actually good for, and why it is not a security measure

Flattening a PDF - What It Locks In, and What It Doesn't Hide

Forms versus comments, why portals and printers want flat files, and why flattening is not redaction