There are a few different ways to remove Cydia from your iPhone. One way is to simply uninstall the Cydia app. This can be done by going into Settings > Applications and finding the Cydia app. Once you have found it, tap on it and then press the Uninstall button. Another way to remove Cydia is to use a jailbreak removal tool such as SemiRestore or iLEX RAT. These tools will restore your device to its original factory state, which will remove all traces of Cydia.