The example you posted will not work like that in PL/SQL.
If you would like to insert multiple columns in the same table you can do 2 things. You could use multiple insert into statements.
For example:
INSERT INTO Billing(Emp_Id, Biling_Date) VALUES ('1001', '2017-06-08');
INSERT INTO Billing(Emp_Id, Biling_Date) VALUES ('1002', '2017-06-08');
Or you could make a procedure where do the insert in the table, and then call that procedure. That way you don't have to constantly write out all column names.
For example:
CREATE OR REPLACE PROCEDURE InsertBilling (nEmp_Id IN NUMBER, vBiling_Date IN VARCHAR2)
AS
BEGIN
INSERT INTO Billing(Emp_Id, Biling_Date)
VALUES (nEmp_Id, vBiling_Date);
COMMIT;
END;
/
BEGIN
InsertBilling('1001', '2017-06-08');
InsertBilling('1002', '2017-06-08');
END;
/