Customer settings contain all in relation of showing fields at the "My Account" section, as well as address fields or customer form field.
Form this place you may define registration method, if should be limited anyway - by email validation or administrator approval. You may disable registration at all. Standard registration does not include any limitation or validation.
This section is also about hiding or showing additional information at the account of your customer, like auction tab, reviews, courses, and many more.
This is a place to enable a username feature. For newly created customers you may add, as a gift, free shipping for first order.
Important tab which defines the security of your customers accounts. So you may define type of format for password, add rule to force customers to use a strong passwords, force customers to change a password per specific period of the time.
Another protection is using Two Factor Authentication feature. Learn how to set it up. [MORE]
That is a predefined list to show your customer during the registration process.
That is a predefined list of address fields form