Hidden Fields can make your typeforms more personal, and adding Logic lets people see only questions that are relevant to them. This article lets you combine the power of these two features by adding Logic to Hidden Fields.
You can add Logic to Hidden Fields just like you would to any other question type. A great example of this would be calling people by their names when they open your typeform, if you already know who they are, and asking them what their name is, if you don’t.
Go to Advanced Logic and set up your Branching and calculations like so:
This way, when the Hidden Fields are already populated, Jon will see the “Hello Jon, good to see you :)” Statement after the Welcome Screen, but when you're using a URL with name=xxxxx as Hidden Fields, people will see the “Hello stranger! What’s your name?” question.