Licences about Adobe Sign and Power Automate

Hello everyone,

I'm actually looking for a solution for PDF signatures, Adobe Sign in Power Automate looks like what I need.

The issue is that I have no idea if the people that are required to sign the document needs a licence, or I need only the one account that is needed to launch the flow in the first place to have a licence and everyone else can run the signing part "freely".

I didn't seen it reading the implementation documents!

Thanks for your help!