An electronic device , comprising: a housing; a display exposed through one side of the housing; an input device configured to be detachably attached to or inserted into the housing; a processor located in the housing and electrically connected to the display; a non-volatile memory electrically connected to the processor and configured to store a memo application; and a volatile memory electrically connected to the processor , wherein the non-volatile memory is configured to store instructions that, when executed by the processor , configure the processor to: while the display is turned off or in a low power state, detect a change of state of the input device from a state in which the input device is attached to the housing to a state in which the input device is detached from the housing; in the low power state, load a first part of the memo application and a second part of the memo application in the volatile memory, in response to the detected change of state of the input device , in the low power state, receive an input on a memo area of the display, which is activated for the memo application, and in response to the input, display an image and/or a text generated by the loaded first part and second part of the memo application on the display in the low power state. a housing; a display exposed through one side of the housing; an input device configured to be detachably attached to or inserted into the housing; a processor located in the housing and electrically connected to the display; a non-volatile memory electrically connected to the processor and configured to store a memo application; and a volatile memory electrically connected to the processor , wherein the non-volatile memory is configured to store instructions that, when executed by the processor , configure the processor to: while the display is turned off or in a low power state, detect a change of state of the input device from a state in which the input device is attached to the housing to a state in which the input device is detached from the housing; in the low power state, load a first part of the memo application and a second part of the memo application in the volatile memory, in response to the detected change of state of the input device , in the low power state, receive an input on a memo area of the display, which is activated for the memo application, and in response to the input, display an image and/or a text generated by the loaded first part and second part of the memo application on the display in the low power state. while the display is turned off or in a low power state, detect a change of state of the input device from a state in which the input device is attached to the housing to a state in which the input device is detached from the housing; in the low power state, load a first part of the memo application and a second part of the memo application in the volatile memory, in response to the detected change of state of the input device , in the low power state, receive an input on a memo area of the display, which is activated for the memo application, and in response to the input, display an image and/or a text generated by the loaded first part and second part of the memo application on the display in the low power state. <EOS>