A method of performing an operation in an image forming apparatus by using a workform which defines one or more workflows indicating one or more operations to be performed with respect to input data includes: receiving identification information of a user of the image forming apparatus; with respect to a workform selected by the user from among one or more workforms pre-existing in the image forming apparatus, determining whether there exists a workform which is redefined corresponding to the received identification information; and if it is determined that there exists the redefined workform, performing an operation according to the workform which is redefined corresponding to the identification information.