If you want to organize online polls that many people can participate in easily, what software can you use? What software meets the criteria of open source, security, transparency, good documentation, scalability, flexibility, etc.?

This question is relevant because establishing a “company owned by humanity” requires a solution that enables people to participate in voting on matters concerning this company.

Which software may only be suitable for smaller communities? Are there technical solutions for voting software that could theoretically be scaled to the entire world population?