If you are looking for how to reset an iPhone 4s you are going to come up with a few different answers depending on the specifics of what you are looking for. This could mean something as simple as returning it to its base settings, or as complicated as clearing all content off of it and starting over. Here is a guide o how to reset an iPhone 4s in a few different ways, meeting a few different needs.
The most basic way to do an iPhone 4s reset is to just reset the settings, which will undo any changes you have made and return it to the factory defaults. Go into Settings and then select General, which is in the third block of options down. Go to the very bottom option, which says Reset. This is going to give you several options on how to reset the iPhone 4s. The top one is Reset All Settings, which will simply restore the default pattern that was there when you first activated your iPhone. After that is Erase All Content and Settings, which is more direct to the iPhone reset request. This is going to absolutely remove all apps, Contacts, and media that you have on your iPhone 4s, as well as return all settings to the default. This content should be backed up on your home computer and you can return it to the iPhone during a hard sync.
Below these two primary options will be a few more specific ones. Reset Network Settings will not change the content or functionality of the iPhone itself, but can be a way to clear out network specifics and can be the right kind of “iPhone reset” if you are having consistent connectivity and service problems. Below that will be Reset Keyboard Dictionary, Reset Home Screen Layout, and Reset Location Warnings. These are all incredibly specific to how you have customized your iPhone, especially how you type or set locations, and is a good way of isolating certain elements that have become cluttered or problematic.
In terms of hardware, resetting an iPhone usually requires you to simply turn it off and on. Hold the home screen and the sleep / wake button, located on the top of the device, at the same time for several seconds. This will essentially turn your iPhone off, and repeating this action will return it to working order. This is one of the more practical solutions for simple problems like a frozen app or internet connectivity problems. It does not permanently change anything and may be the safest reset option.