Our solution is designed from the ground up with the idea of helping you Stamp PDF files online, easy and for free. Transparent background & high resolution images. Make a physical rubber stamp easily. Add a stamp to PDF free. In Acrobat, go to Tools > Stamp. You can remove the stamp at any time with the X in the top Create a custom stamp or custom dynamic stamp. Make a physical rubber stamp easily. Is this correct? It will now appear under Custom Stamps. Works with e-documents & rubber stamps.