Reordering pages is easily done with the print system of your operating system.
I don't count signing as editing really as the structure and content do not change, you sre just attaching s certificate. Th spanish government offer/maintain an open source java tool to digitally sign pdfs:
https://administracionelectronica.gob.es/ctt/clienteafirma
https://github.com/ctt-gob-es/clienteafirma/
I've also copy pasted scan of my signature on contracts using Gimp in order to not have to print them, it is fairly easy.
For the rest I would tend to ask first for thread original working document if I don't have it already. Having said that I have edited in a hurry an old cv for my partner using libreoffice draw in the past.
