An electronic device attachable to an inside of a first vehicle and configured to be coupled to a head-up display and at least one sensor included in the first vehicle, the electronic device comprising: a communication interface; a memory configured to store instructions; and at least one processor connected to the communication interface and the memory, characterized in that the at least one processor is configured to execute the stored instructions in order to: acquire, from the at least one sensor included in the first vehicle, information on a plurality of objects located within a designated distance from the first vehicle; in response to detecting an input for switching on a turn signal to indicate an intention to change a lane of the first vehicle, identify, among the plurality of objects, a second vehicle related to a direction indicated by the input, wherein the second vehicle is different from the first vehicle; determine a distance from the second vehicle based on the information on the plurality of objects; while the turn signal is switched on, determine a form of a content to be displayed through the head-up display, wherein the content comprises a text for guiding a timing and an augmented reality, AR, image showing a path to change the lane of the first vehicle based on the distance from the second vehicle; and display, through the head-up display, the content for guiding an operation of the first vehicle, based on the determined form of the content. a communication interface; a memory configured to store instructions; and at least one processor connected to the communication interface and the memory, characterized in that the at least one processor is configured to execute the stored instructions in order to: acquire, from the at least one sensor included in the first vehicle, information on a plurality of objects located within a designated distance from the first vehicle; in response to detecting an input for switching on a turn signal to indicate an intention to change a lane of the first vehicle, identify, among the plurality of objects, a second vehicle related to a direction indicated by the input, wherein the second vehicle is different from the first vehicle; determine a distance from the second vehicle based on the information on the plurality of objects; while the turn signal is switched on, determine a form of a content to be displayed through the head-up display, wherein the content comprises a text for guiding a timing and an augmented reality, AR, image showing a path to change the lane of the first vehicle based on the distance from the second vehicle; and display, through the head-up display, the content for guiding an operation of the first vehicle, based on the determined form of the content. acquire, from the at least one sensor included in the first vehicle, information on a plurality of objects located within a designated distance from the first vehicle; in response to detecting an input for switching on a turn signal to indicate an intention to change a lane of the first vehicle, identify, among the plurality of objects, a second vehicle related to a direction indicated by the input, wherein the second vehicle is different from the first vehicle; determine a distance from the second vehicle based on the information on the plurality of objects; while the turn signal is switched on, determine a form of a content to be displayed through the head-up display, wherein the content comprises a text for guiding a timing and an augmented reality, AR, image showing a path to change the lane of the first vehicle based on the distance from the second vehicle; and display, through the head-up display, the content for guiding an operation of the first vehicle, based on the determined form of the content.