Avoid direct sunlight to your phone. While leaving it easily accessible may be good for you, it is terrible for your phone. Your phone catches light and heat from the sun and retains it, getting hotter the longer it remains in the sun. Avoiding direct sunlight and heat is the easiest way to prevent overheating your phone.
Turn off unused apps on your phone. Allowing apps you’re not using to run in the background drains the battery and increases the heat on your phone. On an iPhone for example, all you have to do is simply press your home button twice and swipe the apps away. Closing these down not only saves battery but also decreases how hard your phone works, which in turn decreases heat.
Don’t turn your brightness up, buy a glare screen. Just the same as running background apps, turning your brightness up will force your battery to work harder. Instead of turning your brightness up, buy a glare screen. You’ll be able to use your phone in the sun no matter how bright it is.
This one is simple, if you’re not using your phone, turn it to airplane mode or turn it off. Putting it in airplane mode will allow you to continue to use basic functions on your phone but that will be it. These two options make it easier to save your battery and prevent it from heating up.
If your phone is already overheating, take your case off. If your phone is hot, your case traps the heat. Taking the case off will allow the phone’s heat vents to do their job fully without being blocked. This will help your phone cool down quicker.
Keep your applications up-to-date. This one might seem counter-intuitive, but many app updates include bug fixes that can improve your phone’s efficiency. If your phone is already hot, here’s a bit of cure: Fan your phone, or blow on it. You might feel silly fanning your phone, but physics doesn’t care. Just as fanning keeps a body cool, a breeze can help cool off your device when it’s getting too toasty. Wave your hand or a sheet of paper to make a breeze, or even blow on the back of your phone to help it cool down.
http://www.ttechbay.com/2018/06/07/tips-to-keep-your-phone-from-overheating/