As a feature of the Pro plan, App Creators may designate specific columns as containing personally identifable information (PII), and indicate that AppSheet should not retain any information about those columns in the system logs.
Once correctly configured, if you update a record with a PII column, AppSheet's system logs would not record those columns. They simply get passed along to the backend source of data.
To mark a column as PII, set the Sensitive? flag in the column definition dialog, as show below
This only indicates that the column contains sensitive data. It does not tell the system to avoid logging data in this column. To take this additional step, turn on the option via the Account -> Settings pane.