Like computers, smartphones can catch viruses. This can lead to data theft , spam, or malicious software. This can cause the smartphone to crash. The good news is that smartphones are easier to keep virus-free than computers. For this , you have to download the app from the official app store of the manufacturer of the smartphone and make sure that it is a good manufacturer . This means that only well-established apps can be downloaded. Unknown app cannot be downloaded. You can also install Virus Guard.