PDF tools guide
Choose the right tool for your PDF
A PDF preserves a page's appearance, but that does not make every PDF easy to edit or convert. Start by deciding whether you need different pages, a smaller file, editable content or a safe disclosure.
Updated 23 September 2026. This guide covers RedactNinja PDF. Open PDF tools.
Combine or rearrange documents
Use Merge PDF when a report and its appendices need to become one file. Use page organisation to change the order or remove pages. Split and extract are for producing separate documents from a larger file.
- Keep a copy of each original, then open the relevant tool and select your files.
- Check the order using the page previews. A filename or the order files were selected is not proof of the correct reading order.
- Download the result and check the first and last page of each section, page orientation and total page count.
Removing a page removes it from the output document; cropping a page is different. Cropping changes its visible boundary and should not be used to remove confidential content.
Convert Word, Excel or PowerPoint to PDF
The browser converter supports subsets of DOCX, XLSX and PPTX content. It is useful for straightforward documents, but does not use the desktop Microsoft Office rendering engine. Do not assume that older DOC, XLS or PPT files are interchangeable with these formats.
After conversion, compare headings, images, tables and the end of each page with the original. Word headers and footers, floating objects and unusual fonts may not reproduce as expected. Spreadsheets need particular attention to which sheets and cells appear. Slide layouts can change when fonts or unsupported objects are involved.
For an exact copy of a complex Office layout, use the originating application's PDF export and bring that PDF into RedactNinja for the remaining page tasks.
Convert a PDF into an editable file
A PDF usually records where text and graphics sit on a page, rather than the original paragraphs, spreadsheet formulas or slide objects. Converting it back cannot reliably recover everything that created it.
PDF to Word reconstructs supported content, but a complicated multi-column page may need editing afterwards. PDF to Excel produces extracted content, not the original workbook logic. Do not rely on it to recreate formulas. PowerPoint output may use page images rather than individually editable objects. Check the conversion options and output before choosing a format.
For notes or documentation, PDF to Markdown offers another route. Check reading order, headings and table boundaries, especially where the source uses columns or irregular spacing.
Make a file smaller without losing readability
Compression is most useful when a PDF contains large images or scans. A short text-only PDF may already be small. Stronger image compression can blur fine print, diagrams and signatures.
- Start with a moderate setting and retain the original.
- Compare the output file size with the source.
- Zoom in on small text and detailed images. Check the document at its intended print size as well as on screen.
- Use a gentler setting if the smaller output is difficult to read. A smaller file is not automatically a better result.
Make a scan searchable
If you cannot select words in a PDF, its pages may be images. OCR attempts to recognise that text. Choose the appropriate language, straighten the scan where needed and use a clear source image.
Check names, dates, reference numbers and table columns after recognition. A page containing some selectable text can still include scanned sections. Searchability is not proof that every part of the page was recognised, and a poor scan cannot always be repaired through OCR.
Edit, fill or sign
Adding text is useful for labels and simple corrections; it is different from reconstructing a document's original paragraphs. Use form tools when the recipient needs interactive fields rather than text drawn on top of a page.
A placed signature image is a visual mark. A certificate signature serves a different purpose and needs certificate verification. Editing a digitally signed document can affect the signature's validity. Keep the signed original and inspect the final result.
Handle sensitive information separately
Do not cover confidential words with ordinary shapes and assume they have been removed. Use a redaction workflow, then check the exported document. For a Subject Access Request involving several documents, email evidence or recorded review decisions, open the SAR workspace.
Conversion, compression and cropping are not redaction. A technical verification result also cannot establish that you found every sensitive detail.
If the result is incomplete
Keep the source file. Try a smaller selection to establish whether one page or object causes the problem, and note the tool name, browser and error message. Do not repeatedly use a damaged output as the next source.
Report a problem using a fictional example where possible. Do not email sensitive records, case passwords or certificate credentials. For archiving, do not treat a prepared PDF/A output as conformant without an appropriate independent validation result.