Personal data is, in nature, of different sensitivity. For instance, social security number, has a higher level of sensitivity than say an address. You have to have special needs to save a social security number and a number of security measures compared to the address. On Agent Portal > Configurations > GDPR Management > Personal Data Sensitivity Levels you add levels that suits your organizations data structure. The level is then assigned when you define Personal data fields.
The system has no default levels, so these must be added before the GDPR functionality can be up and running.