PDF and text
What is PDF?
Short for Portable Document Format.
PDF is a document format designed to look the same on every device, preserving fonts, layout and images exactly as they were set out.
How it works
A PDF describes each page precisely: where every character, line and image sits. That is what makes it look identical on a phone, a laptop and a printer, and why it is the standard for forms, contracts, invoices and anything meant to be printed.
A PDF can contain real text, vector graphics and raster images. Some PDFs are scans consisting only of pictures of pages. Others include selectable text. This difference affects searching, copying, accessibility and how far a file can be compressed.
Pages are independent, so combining, splitting, reordering, rotating and deleting them are quick, lossless operations. Changing the words on a page is much harder, because the file stores positioned glyphs rather than editable paragraphs.
A practical example
An invoice exported from a word processor has selectable text. A scanned copy of the same invoice may be only pictures of pages and need OCR before its words can be copied.
What to watch out for
Changing a filename to .pdf doesn’t create a PDF. Converting pages to images can also remove selectable text, links and form fields.
Tools you can use
- Merge PDF · Combine PDFs, in the order you choose
- Compress PDF · Shrink the images, keep the text sharp
- PDF to Text · Copy the words out, in reading order
- Split PDF · Pull out page ranges or separate every page
- Delete PDF Pages · Remove pages you don’t want
- Reorder PDF Pages · Move pages into the right order
- Add Page Numbers to PDF · Position, format, start number, skip the cover
Go a little deeper
- How to add page numbers to a PDF
- How to combine PDF files into one
- How to compress a PDF for email or an upload limit
- How to delete a page from a PDF
Common questions
Why can’t I edit my PDF?
PDF is built for final layout, not editing. Text is placed as positioned fragments rather than flowing paragraphs, and scanned PDFs contain no text at all. Page-level tasks such as merging, splitting and rotating are easy; rewriting text needs a dedicated editor.
Why is my PDF so large?
Usually high-resolution images or scanned pages. Compressing those images makes the biggest difference; PDFs that are mostly text are already small.
Is a PDF secure?
Not by default. Anyone who has the file can usually copy or extract its contents. Password protection helps, and blacking out text only hides it unless the underlying text is removed.