Permanently merge checkboxes, text fields, and comments into your PDF document. Ideal for securing forms, signatures, and preventing future edits.
Click to select a file or drag and drop
Single or multiple PDF files supported
Your files never leave your device.
Note: Flattened content cannot be edited or filled out.
Processing...
Select one or more PDF files from your device or drag and drop them into the upload area.
Click 'Flatten PDF(s)'. Our tool instantly merges all form fields and annotations into the document layer.
Save your flattened, non-editable PDF instantly. Multiple files are bundled into a convenient ZIP archive.
Remove metadata, annotations, scripts, and more.
Strip comments, highlights, and links.
Fill in forms directly in the browser. Also supports XFA forms.
Reduce the file size of your PDF documents while maintaining the best possible quality.
Annotate, highlight, redact, comment, add shapes/images, search, and view PDFs.
Flattening is the process of merging interactive elements like form fields, checkboxes, and comments into the background of the document. Once flattened, these elements become part of the static content and can no longer be edited.
Flattening is crucial before sharing signed or completed forms. it prevents others from changing your answers, moving annotations, or altering signatures, providing an extra layer of security.
No. Once a PDF is flattened, the interactive fields are permanently converted into regular graphics and text. We recommend keeping a backup of the original interactive file if you need to edit it later.
In many cases, yes. By removing the complex metadata associated with interactive forms and annotations, the resulting file can be smaller and faster to load on all devices.
Absolutely. ZentoPDF uses local browser-based processing (WebAssembly). Your documents never leave your computer, ensuring total privacy and data security.