receiving a user input to request execution of the application;

outputting a first audio signal indicating a first induced inquiry corresponding to a first input field among a plurality of input fields, when the user input is a voice input, wherein, the plurality of input fields include an essential input field and an additional input field, and the first induced inquiry is only generated for the essential input field;

receiving a first voice input indicating a response to the first induced inquiry;

transmitting identification information of an application, identification information of the plurality of input fields, at least one second value inputtable to the essential input field and identification information of a page including the plurality of input fields;

receiving, from a server, at least one third value inputtable to the essential input field;

detecting a value for a second input field which is essential field from the received first voice input:

setting a first input value for the second input field based on the detected value and the at least one third value;

setting a second input value for the additional input field to a preset default value; and

executing the application by outputting a second audio signal indicating a second induced inquiry corresponding to a third essential input field for which a third input value is not set among the plurality of input fields.