Filled in a PDF form and need it locked so the answers cannot change? This free Flatten PDF Form tool seals it. Upload the form, click Flatten, and download a fixed PDF. Useful when answers are final:
- Lock a completed application form
- Seal a signed agreement before sending
- Prevent edits to submitted answers
- Archive a finalized form as flat data
A Quick Word on IronPDF
IronPDF is the C# PDF library trusted by thousands of .NET developers in production. It flattens interactive form fields into static content from code, baking the answers permanently into the page.
using IronPdf;
var pdf = PdfDocument.FromFile("filled-form.pdf");
pdf.Flatten();
pdf.SaveAs("flattened.pdf");See it in C#: Flatten form fields
Free and Built for Everyday Use
This tool is completely free and made for quick, practical use, no signup, no limits, no catch. Built with love by IronPDF.
Need More Than PDFs?
When the project grows beyond PDF work, the Iron Suite bundles ten .NET libraries into a single license: IronOCR for reading text from images in 125 languages, IronBarcode for generating and scanning codes, plus IronXL, IronWord, IronPPT, and more. Start your 30-day Iron Suite trial key today, no credit card required.
