Reset iPhone

What kind of reset?

• Normal restart (RESTART your iPhone, iPad, or iPod touch - Apple Support): All of your apps are “told” to save their work and shut down, then iOS shuts down until you restart it.
• Force restart (If your iPhone, iPad, or iPod touch won't turn on or is frozen): all of your apps are terminated immediately, without being given the chance to say any work in progress, and your phone restarts.
• Erase all content & Settings: All of the user storage on your phone is cleared and all content other than iOS is permanently erased, and iOS settings are reset to their default values.
• Restore using your computer: All storage is cleared and erased, including iOS, and a new “clean” copy of iOS is installed.

After the last two above if the phone has Activation Lock enabled it will be necessary to enter the Apple ID and password that were used to set it up before the phone can be used again. Once that is done you can either restore a backup or set the iPhone up as a new device.

If this doesn’t answer your question please expand on what you want to know.