Follow these steps to configure the Accounts and Privacy settings:

1. Click the Accounts and Privacy tab alongside the Payments tab on the same screen.
2. In the Guest checkout section, disable the Allow customers to place orders without an account setting and enable the Allow customers to log into an existing account during checkout setting.
3. In Account creation, enable the Allow customers to create an account during checkout setting.
4. Click the Save Changes button to save the Accounts and Privacy settings.