The Motorola Moto G3 (Model Number: XT1540) is the 3rd generation android phone produced by Lenovo. It can be identified by its 5.5 X 2.8 inch screen. There are two speakers on both the top and bottom of the front screen.
@akash03 either replace the headphone jack or check the copper "legs" to make sure they are still making contact. Either use this video or this one in reverse to get to the jack. It is a modular jack and does not require soldering etc.