PDF4 is an all‑in‑one mobile PDF toolkit for scanning, editing, converting, and securing documents directly on your device. It combines robust editing features, like modifying text, images, and pages, merging and splitting files, reordering or rotating content, with powerful conversion tools to transform images or Office formats into PDFs and vice versa (e.g., PDF to Word, PowerPoint, or Excel). It supports OCR for searchable text extraction, password protection, annotations, and form filling. Users can compress files, crop pages, add metadata, watermarks, or barcodes, and leverage automation such as job‑flows for batch processing on a desktop. Extended integrations include browser extensions, Zapier/Power Automate connectors, and Microsoft Teams/Outlook add‑ins, enabling seamless PDF workflows across platforms.