I don’t know much about penetration testing so excuse me for the dumb question: are you required to disclose the exact methods that you’re going to use?
It is very varied. There are a lot of good and enjoyable stories out there on youtube and podcasts for anyone interested.
With every pentesting engagement I've had, there always were rules of engagement, and what kind of things you are and are not allowed to do. They even depend on what kind of test you are doing. (for example: if you're testing bank software, it matters a lot if you test against their production environment or their testing environment)