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?

Yes. You have agreements about what is fair game and what is off limits. It can be that nothing can be physically altered, what times of day or office locations are OK, if it should only be a test against web services or anything in between.

Do you? You have agreement with part of the company and work it out with them, but does this routinely include the people who would be actively looking for your intrusion and trying to catch it? Often that is handled by automated systems which are not updated to have any special knowledge about the up coming penetration test and most of those supporting the application aren't made aware of the details either. The organization is aware, but not all of the people who may be impacted.

Exactly. That's answered higher up in the comment tree you are responding to.

It depends on the organization. Most that I've worked with have said everything is fine except for social engineering, but some want to know every tool you'll be running, and every type of vulnerability you'll try to exploit.

Yes, and a bank branch for example could be very interested in some social engineering to test physical security.

It is very varied. There are a lot of good and enjoyable stories out there on youtube and podcasts for anyone interested.

I tried google much but there were too many results haha. Do you have a few that you recommend?

What you do during pentesting is against the law, if you do not discuss this with your client. You're trying to gain access to a computer system that you should have no access to. The only reason this is OK, is that you have prior permission from the client to try these methods. Thus, it is important to discuss the methods used when you are executing a pentest.

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)

usually the discussion is around the end goals, rather than the means. But both are game for discussion.