Làm Phẳng PDF - Khóa Trường Biểu Mẫu và Chú Thích

How to Flatten a PDF

Upload PDF

Select the PDF file with form fields or annotations you want to flatten.

Flatten

Click the 'Flatten PDF' button to convert all interactive elements into static content.

Download

Download your flattened PDF with all fields permanently locked.

Why Flatten Your PDF?

100% Private

All processing happens in your browser. Your documents never leave your device.

Free & Unlimited

No registration, no limits. Flatten as many PDFs as you need, completely free.

Preserve Appearance

Form values and annotations are preserved visually while becoming permanent and tamper-proof.

Frequently Asked Questions

What does flattening a PDF do?

Flattening converts interactive form fields (text boxes, checkboxes, dropdowns) and annotations into static content that cannot be edited.

Will the form values be preserved?

Yes! The current values in all form fields are preserved visually. They simply become part of the static page content.

Can I undo flattening?

No, flattening is permanent. We recommend keeping a copy of the original PDF before flattening.

Why would I want to flatten a PDF?

Flattening is useful for finalizing forms, preventing editing, reducing file size, and ensuring consistent appearance across different PDF viewers.

Is my PDF uploaded to a server?

No. All flattening happens in your browser using WebAssembly. Your PDF never leaves your device, making it safe for sensitive documents.

Does flattening reduce file size?

It can. Removing interactive form elements and simplifying the PDF structure often results in a smaller file size.

Does this work on mobile devices?

Yes. The tool runs entirely in your browser on any device — desktop, tablet, or smartphone. No app installation required.

Will the flattened PDF look the same?

Yes. The visual appearance is preserved exactly. Form fields show their filled-in values, and annotations remain visible — they just become non-editable.

Flatten PDF