How to properly handle sensitive information in Data 360 is a deep topic, but there are several key security and privacy features to be aware to help you secure sensitive data covered well in this blog. (TLDR: private networking, platform encryption, data spaces, tagging and classification, and access policies)
Finally, review Salesforce's Data Protection and Privacy guides to help you meet regulations like GDPR, CCPA, PIPA, etc. across their products.