when using Family Sharing on an iPhone, if you turn off your location sharing, your parents (or the Family Organizer) will receive a notification stating that "Your [your name]'s location is no longer available" or something similar. This notification informs them that you have disabled location sharing with the Family Sharing group.
Keep in mind that Apple's features and policies may change over time with software updates and new iOS versions. Therefore, it's always a good idea to check the latest information in the Settings or Apple Support documentation on your iPhone to ensure you have the most up-to-date details regarding location sharing and Family Sharing settings.