I personally believe that the iPhone has a few extra securities than the Android devices. It seems that more people attack the Android IOS than they do the iPhone. Each phone has new securities with each update and each time a company update the software they fix the vulnerabilities in the previous version of the software.
Today, each mobile device manufacturer has done their best to secure your mobile device. The iPhone uses a secure login through the iCloud where the Android now uses your Google Account to secure your login on the device.
In order to keep your phone safe, check out the downloads before installing them on your device. There is some download that can harm your phone and corrupt your software. It is recommended that you take caution when surfing online, downloading, and viewing some website. Keep your WiFi connection turned off when you are out and about and only connect to a secure WiFi if you need to when you aren't home. Basically, you'll follow the same procedures on your phone as you do on your computer or laptop. Just be careful when surfing online and attaching your device to an unsecured WiFi connection.