1. Don't install apps that you don't know about, don't give strangers any food just like you don't eat , don't install any unfamiliar apps. Currently, hackers send messages via emails , messages, etc. to install their apps. Don't go for less that your full potential. It may be that hackers will take away all your information through this app. 2. Install apps from Google Play or trusted App Store Where do you usually buy food ? From the sidewalk or from a safe store in the fridge ? Of course from the safe store. Download such apps from Google Play or any secure app store ( Amazon App Store and not bad) they check each app separately. So naturally the app stores are much safer. 3. " Install from unknown sources" - Keep off Install from unknown sources means the app can be installed from any place other than the verified app store. But it has a lot of security risks. And mark it in Verify Apps . This will confirm your device about the app from the net before installing any app. 4. Read the permissions before installing the app. This is the best way to avoid unwanted apps. After reading the permissions , you will understand what this app can access to your device. If you think it wants access to something that doesn't work , it's best not to install the app. And if you want to access your device's Contacts, Account Information, then think once to install. 5. Many people can install antivirus using antivirus on mobile. Many do not. What should you do ? In this regard, I would say that if you install everything from Google Play or a verified app store, then you do not need to install any antivirus . Google Play scans each app perfectly. However, you can install Antivirus for extra caution .