Script to sign any PDF
First, install pdftk and wkhtmltopdf (Debian 10)
sudo apt install pdftk
sudo apt update
sudo apt -y install wget
You must pass the document to be signed as an argument, then the PDF where the signature will be placed, 3 the destination of the signed file and finally the number of sheets to sign
For example
./firma_documento.sh doc.pdf sign.pdf dest.pdf 4-5
(change path for your computer files in the script)