Paypal name for single name

Based on my friend name who's want to open an paypal account and he was confused while filling the form application because he has single name only. he worried, it will be a problem when he want to do transaction in the future, and then he ask me about it. According to my experience we could put the same name on First name or Last name, and also we may put FNU ( First Name Unavailable ) on First name.
Don't forget to do the same way when you fill other registration form and fill it with the valid data.