Hello Jan, could you answer the last question that Ante asked? It seems like you're the expert. I used https://pdfliner.com/sign_pdf_online for signing my PDF files, but if there's a better way to do something, I'm always for that. I love finding new and better ways to do things. It's always nice to learn something new.
Still, that website had helped me many times when I struggled with finding the right form in a PDF format. Anything not in PDF is bad because you might have problems afterward with printing it and other stuff.
I will be waiting for your response, and I hope you have something useful for us.