Firstly children should not be given mobile phones. It harms the brain development , and has many more harmful effects. Give healthy homemade food when he is hungry . Keep adequate gap between feeds . If he is underweight or anemic , he may need supplements , so please ask  your Paediatrician to examine him and advise accordingly.

Good morning, never force him to eat food, max time you can spend is 15 to 20 min for each meal, after that give him some time and give some new food. Try to avoid gadgets because they divert his mood from eating, chewing and enjoying food tastes, it may take 1 to 2 weeks but definitely he will improve and start eating