INSERT INTO fss_Person (personname,personphone,personemail)VALUES ('$fName','$phone','$email')  the primary key for this table is auto generated

INSERT INTO fss_customer (custid,custregdate,custendreg,custpassword)VALUES ('$custid' ,'00-00-00','00-00-00','$password')

$getID="SELECT personid FROM fss_person WHERE fss_person.personname ='fName'";

$insertPassword = "INSERT INTO fss_customer (custid,custregdate,custendreg,custpassword)VALUES ('$getID' ,'00-00-00','00-00-00','$password')";