You can get a whole lot of free apps on your mobile today than ever before. However, you would have to endure the Ads they bring along with them. Moreover, some of them may not be trustworthy and may contain malicious code that may compromise the security of your device.
This situation is all the more likely to happen with Android devices as the OS is open source,making it easier for malware to enter it. You can ensure that viruses and malware are removed from the device by regularly purging them from your mobile.
The following steps can be taken by you to ensure your device remains free of viruses and
a) Do not download apps from unknown sources. Use the Play Store to do so. Do not get tempted by free offers of wonderful apps and download or install them without checking out reviews of such apps.
b) If you suspect certain apps to be infected and wish to remove them, first get the device into the Safe Mode. This can be done by pressing the Power Off button to get the Power Off option and then holding this button to get a restart in Safe Mode.
c) You can now get into the Device Settings and choose the Apps that have been downloaded. Just browse through the list to check if there are apps you are not aware of, not using or suspect them to have been infected.
d) Once you have identified the suspicious apps, tap on them and choose uninstall. Some of them may not allow you to Uninstall if they have become infected and the Virus has assumed the status of Device Administrator. You therefore need to go the Device Administrator of your device where you will see the entire list of apps with you as the owner of the device being the Administrator. It would now be possible for you to uncheck the suspected apps and tap Deactivate to render the apps inactive.
e) Now you may restart your smart phone to bring it out of safe mode. Having removed the offending virus and malware, you need to keep checking your mobile on a regular basis for such apps occupying the space on your mobile and purge them periodically. This will ensure smooth functioning of your mobile at all times.