How to fill and annotate a PDF online
How PDF filling works in the browser
PDF.js renders a local preview of each page. Your item positions and sizes are stored as proportions of the visible page, so they remain aligned when you zoom the preview. During export, each item is rendered locally as a high-resolution image and PDF-lib draws it onto a copy of the selected PDF. Existing page content is not intentionally rasterized, and the original file is not overwritten.
Text and note fields accept up to 500 characters, font sizes are limited to 8–72 points, one PDF can be up to 200 MB, and a document can contain up to 250 added items. These are browser-safety guardrails rather than guarantees: available memory, complex PDFs, and mobile hardware may impose lower practical limits.
Important: The exported additions are flattened visible graphics, not interactive AcroForm or XFA fields and not PDF comment objects. Editing a certificate-signed PDF can invalidate its existing digital signature. For official forms, regulated submissions, or legal documents, confirm the recipient’s format and signing requirements. This tool does not provide legal advice.
Last implementation review: 28 July 2026. Open the downloaded copy and inspect every edited page before sharing it.