What is the voting/decision-making service with delegation of votes?

Question

Project management

We need a service that can create voting for decisions for working groups with the following functionality:
1. You can delegate your votes in specific votings to other users.
2. Votes can be withdrawn at any time.
3. It is desirable that the service be free/inexpensive with no restrictions on the number of users. Or Open Source with installation on your server.
4. Preferably with API.
5. Preferably with mobile applications.
Thank you!

Answer 1

look at google forms. I'm not sure all functionality is there. But questionnaires (voting) can be created.