About Flatten PDF
Flattening a PDF removes all interactive elements and merges them permanently into the page content. Form fields, annotations, text highlights, and signature placeholders become static visual elements that can no longer be edited or clicked. This is an essential step before final distribution of completed forms, signed documents, and reviewed drafts.
When you receive a PDF form, fill it in, and flatten the result, the field values become part of the permanent page content. Recipients see the filled form exactly as you intended, with no ability to change the values. This also prevents the common issue where form data appears blank when a PDF is opened in a different reader application.
LocalPDF's Flatten tool processes your document locally using pdf-lib. The form fields are removed and their current values are rendered as static text on each page. Your document never leaves your browser.
How to Use
- 1Click "Select PDF File" or drag your completed form PDF onto the upload area.
- 2Click "Flatten PDF" to begin processing.
- 3Wait for the tool to remove form fields and lock in their values.
- 4Download the flattened PDF to your device.
Key Features
Permanent Form Values
Form field values are rendered as static text. Recipients cannot change the filled values or see form field boundaries.
Annotation Removal
Highlights, sticky notes, comment boxes, and other annotation layers are flattened into the page content.
Universal Compatibility
Flattened PDFs open correctly in all PDF readers without requiring form support, solving cross-reader compatibility issues.
Client-Side Processing
Your PDF form data, which may contain personal or confidential information, never leaves your device.
Frequently Asked Questions
What is the difference between flattening and printing to PDF?
Printing to PDF re-renders the document through the printer driver, which can alter fonts, colors, and layout. Flattening with pdf-lib preserves the original PDF structure while only removing interactive layers.
Can I unflatten a PDF after flattening?
No. Flattening is a one-way operation. Form fields and annotations are permanently removed. Keep a copy of the original before flattening if you need to make changes later.
Will digital signatures be preserved after flattening?
Basic visual signature images are preserved as page content. Cryptographic digital signatures become invalid after flattening because the document content changes.
Why should I flatten before sending a PDF form?
Unflattened forms can display differently in different PDF readers. Some readers show fields as empty if they do not support the specific form type. Flattening guarantees consistent display everywhere.