An example image forming apparatus includes an input interface, an output interface, a memory, and a processor. The processor is to output information related to whether a function of the image forming apparatus is enabled through the output interface, based on the function of the image forming apparatus being disabled, output information indicating whether a size of the memory corresponding to the disabled function is allocated, and based on receiving a signal to remove a memory size allocated to the disabled function through the input interface, remove the memory size allocated to the disabled function and adjusts an allocation state of the memory size to a user setting state.