Sharing implications of Person accounts and related contacts
Key Takeaway
To share a person account, share the whole account record, because a person account has no separate contact you can share.
A person account stores one individual as one record. Turning on person accounts changes three things for admins: the organization-wide defaults you can use for contacts, how you share and secure person account data, and how person accounts relate to business accounts and contacts. The last change affects what users can see on related records.
What a person account is
Because a person account has both an account and a contact behind it, it behaves partly like an account and partly like a contact. Each person account counts against both account storage and contact storage.