All of Salesforce automation tools support some sort of logic. At the very least, the logic states when the actions of the automation should occur.

Process builder supports additional logic for certain actions. For example, you can update child records and specify logic of which child records should be updated.

The only declarative automation tool that allows complicated logic and automation pathways is Flow. You define these paths with the Decision element!

This episode of Wizard Apprentice is an overview of the Decision element. You will see how to create and defined outcomes and some examples of use cases of when you would want to use a Decision element.

Lightning Flow Builder: Decision Element! Wizard's Apprentice Episode 3