Many forms are just printed pages. Think Pages opens the signing view instead, where you can place text, today's date and ticks anywhere on the page.

No. Your answers are written into the page when you export, so they look the same in every PDF reader and can't be edited by accident.

Yes. Press Sign to draw, type or upload your signature and drag it into place.

No. You fill it in your browser and the finished PDF is made on your device, so personal details on the form stay with you.