Process Builder allows you to launch a Flow. Process Builder is another way to auto-launch a Flow. For example, there is a Flow that allows for the removal of followers from closed opportunity records. If you want this Flow to automatically execute whenever the opportunity status gets closed, you should use Process Builder.
Some Flows don't require any user interaction to start; for example, a Flow of the type Autolaunched Flow. An Autolaunched Flow can be launched without user interaction; from Process Builder or the Apex interview.start method, for example.
Let's look at a business scenario. Suppose that Sara Bareilles, who is working as a system administrator at Universal Containers, has ...
