You can disable fields with CSS that will prevent them from being edited or deleted from the front end. I'd be careful that this practice doesn't run afoul of PII data privacy laws. GDPR is generally the model to follow unless your country's laws are more restrictive. In the US, we use the California and GDPR laws as models to assure data privacy protection. In essence, the laws preserve the idea that PII belongs to the individual that provides it. As such, the individual has the right to delete their PII in any system that holds this information regardless of its location in the world. As a general rule, when we build expert business solutions featuring Formidable Forms, we avoid using an individual's PII as an immutable system identifier, opting instead to construct an identifier that does not use PII.