Fill Forms: how it works
To fill a PDF form, open the Fill Forms tool and add your file; PDFER detects the fillable fields so you can type into them, then flatten and download. The form is filled in your browser and never uploaded.
How to use Fill Forms
- Open the Fill Forms tool and add your fillable PDF.
- Type into the detected form fields.
- Flatten and download the completed PDF.
In your browser vs. uploading to a server
Best for completing application or tax forms privately. Flattening bakes your answers into the page so they can't be changed by the recipient.
Frequently asked questions
How do I fill out a PDF form online for free?
- Open the Fill Forms tool, type into the detected fields, and download; it is free and the form never leaves your browser.
Are my files uploaded to a server?
- No. PDFER runs entirely in your browser using WebAssembly and JavaScript. Your files are read into memory on your device, processed locally, and never sent to PDFER or any third party. Closing the tab or leaving the tool erases them from memory.
PDFER is a privacy-first PDF toolkit built by Kiril Urbonas. Every tool runs entirely in your browser — see our security model and privacy policy.