Choose the PDF you need to sign. It opens at full size next to these controls, so you can check you picked the right file.
A photo or scan of your signature on paper works fine — the paper behind it is removed for you.
Got an official stamp or seal? Drop it in and place it the same way. Don’t need one? Skip it.
When an office only accepts a scan, turn this on and the page is re-rendered like a photocopy. The document view updates as you tune it.
Here is what gets built. What you see on the document is exactly what lands in the file.