An electronic device for providing a memo application comprising: an electronic pen; a slot in which the electronic pen can be inserted or detached; a pen sensing module configured to sense an insertion of the electronic pen inside the slot of the electronic device or a detachment of the electronic pen from the slot of the electronic device; a pen input module configured to receive an input using the electronic pen; a display forming a plurality of layers with the pen input module; a memory storing the memo application; and a processor electrically connected to the display, the pen sensing module, the pen input module and the memory, wherein the processor is configured to: cause the display to enter an OFF state by turning off the display in response to receiving a power or sleep button input or after a predetermined time without a user input; sense via the pen sensing module the detachment of the electronic pen from the slot of the electronic device during the OFF-state of the display; when the electronic pen is completely detached from the electronic device, activate the pen input module, and activate the memo application; the electronic device being characterised in that the processor is further configured to: when the electronic pen is completely detached from the electronic device, display a screen with a background maintaining a black color including at least one control menu. an electronic pen; a slot in which the electronic pen can be inserted or detached; a pen sensing module configured to sense an insertion of the electronic pen inside the slot of the electronic device or a detachment of the electronic pen from the slot of the electronic device; a pen input module configured to receive an input using the electronic pen; a display forming a plurality of layers with the pen input module; a memory storing the memo application; and a processor electrically connected to the display, the pen sensing module, the pen input module and the memory, wherein the processor is configured to: cause the display to enter an OFF state by turning off the display in response to receiving a power or sleep button input or after a predetermined time without a user input; sense via the pen sensing module the detachment of the electronic pen from the slot of the electronic device during the OFF-state of the display; when the electronic pen is completely detached from the electronic device, activate the pen input module, and activate the memo application; the electronic device being characterised in that the processor is further configured to: when the electronic pen is completely detached from the electronic device, display a screen with a background maintaining a black color including at least one control menu. cause the display to enter an OFF state by turning off the display in response to receiving a power or sleep button input or after a predetermined time without a user input; sense via the pen sensing module the detachment of the electronic pen from the slot of the electronic device during the OFF-state of the display; when the electronic pen is completely detached from the electronic device, activate the pen input module, and activate the memo application; the electronic device being characterised in that the processor is further configured to: when the electronic pen is completely detached from the electronic device, display a screen with a background maintaining a black color including at least one control menu.