Document electronic signing (electronic/digital signature)

I’m implementing the project to adding the electronic/digital signature to the PDF. For C# and Java there are some solutions like iText, IronPDF… so I raise the question to get the advice/suggestions if any equivalent library, solutions in eco-stack Elixir/Erlang.
I looked at some libs like: elixir-pdf-generator , chromic_pdf, elixir-pdf… but did not find any functions to signing the electronic signature.
So far, my solution is the C# background application to get the PDF document → sign electronic signature → push back to storage the signed document. But it is better if there are the eco-stack Elixir/Erlang libs to adapting.