An electronic device includes a communication interface, an input interface, a memory storing a message application for transmitting/receiving a message that includes a main message, a display, and a processor. The processor sets a first interaction for displaying a first hidden message on the main message, the first interaction including information about at least one of a type, an input position, an input frequency, an input time, and an input sequence of a user input used to display the first hidden message, generates the message to include the main message and the first hidden message, the message being configured such that the first hidden message is displayed on the main message when the user input used to display the first hidden message and corresponding to the set first interaction is received, and transmits the generated message to an external device through the communication interface.