Create Person Accounts for Self-Registering Users

By default, all self-registering users are assigned as contacts to a single business account. If your business deals mostly with individuals and you prefer to track them as individuals, you can now assign each self-registering user to a person account instead.

To do this, ensure that you have person accounts enabled in your community and leave the Account field blank in the self-registration options; Salesforce will create separate person accounts for each self-registering user. Note that you must specify a default profile to assign them to. You can further customize this functionality using the self-registration Apex controller, but you aren’t required to do this.Create person accounts for self-registering users

Creating person accounts for self-registering users is supported for the Customer Community and Customer Community Plus licenses only.