no need of written agreement.see if it is covered under following classes: The expression, “work” in this section would include-
a. Advertising
b. Broadcasting and telecasting including production of programs for such broadcasting or telecasting
c. Carriage of goods and passengers by any mode of transportation, other than railways
d. Catering
e. Manufacturing or supplying of a product according to the requirement or specification of a customer by using the materials purchased from such customer, But does not include manufacturing or supplying of a product according to the requirements or specifications of a customer by using the materials purchased from a person, other than such a customer