Person account field security, history and formula behaviour
Key Takeaway
Set field-level security for person account fields on the matching Contact field. Track person account field history in the account field history settings, and that includes contact fields such as Email and Mobile.
A person account stores information about an individual by combining one account and one contact into a single record. Its fields come from two objects. So an admin needs to know which object controls field-level security, where field history is tracked, and what formula fields can reach.
Where person account fields come from
Each person account consists of one account and one contact, so its fields are a mix of account fields and contact fields. Contact fields that business accounts don't use appear on person accounts with a Person prefix. Custom contact fields appear on person accounts with a __pc suffix.
You can't edit a person account's Account Name directly. Salesforce builds it from First Name and Last Name, in the order the user's language setting calls for. When Middle Name and Suffix are enabled for the org, Account Name includes them too.
Approval processes for person accounts don't accept Account Name as valid entry criteria. Use the First Name and Last Name fields instead.