Family Access to Information

I am brand new to Apple and the services essentially (got an iPhone for the first time in 2022 now purchased MacBook) My question is what exactly can people that I add to my family plan access. I have personal files that wouldn't be the end of the world if they did see but would prefer them not to. I have apple one and the main purpose of me sharing with them is to allow them to access my Apple TV, music and news. I am nervous to share my iCloud+ because I don't want to unknowingly share access to my personal files. I am just so new to this that I am not sure how to navigate the programs to expertly know what exactly I am providing them access to by sharing.