Apple offers free updates for its iOS mobile operating system, but the iOS 7 is no longer available, as of 2015. Therefore, any updates initiated upgrade the device to the newer iOS 8 version.
Apple ceased digitally signing iOS 7 versions in 2014, meaning that it is no longer possible to install iOS 7 on a standard iPhone or iPad. The easiest way to update an iOS device is to use the Software Update option located in the General section of the Settings app. Alternatively, iTunes can perform updates to a connected device. Apple recommends backing up any iPhone or iPad before updating it, to avoid potential data loss if there is a problem during the update procedure.