I'm currently writing a framework with a team of scientists. We aim to reach a higher impact by getting other scientists to sign this framework. They're not part of the writing team but they would acknowledge the need for this framework and agree to its principles. A bunch of people actually approached us and recommended us to do it that way, so we definitely have the community behind us.
However, what would be an appropriate way to collect those signatures? Surely something like change.org would be not professional and not serious enough. One thing to use would be digital signatures in a PDF document. But what should I do with >50 PDF documents with different signatures on them? Is it possible to merge those documents into one? I'm not sure whether you can copy and paste digital signatures?
I would welcome suggestions on how this could be done in a professional way, resulting in a good looking outcome.