Which tool is best for combining multiple flows that require input from various users?

The Orchestrator is the best tool for combining multiple flows that require input from various users because it is specifically designed to manage multi-user and multi-flow processes. It allows for the coordination of various automated elements and provides greater flexibility in managing complex workflows that involve different participants. Through Orchestrator, you can create a seamless experience where each user can contribute their input at different stages of the process, and it helps in orchestrating the overall flow effectively.

Flow Builder is a robust tool for creating individual flows but does not specifically handle the orchestration of multiple flows and user inputs as efficiently as Orchestrator. Process Builder and Workflow Rules are primarily used for more straightforward automation scenarios, focusing on individual processes rather than the combination and management of multiple user inputs across different flows.