Don't know how to reset my device (iOS)

1. Go to Settings -> Tap on General -> Select Reset
   
      
   
   
   
2. Tap on Reset All Settings -> Enter the password of the synchronized account -> Tap on Reset All Settings
   
   

        
   
   

If you have exhausted every method to increase the speed of your mobile device and without success, there is only one more thing left to do. A hard reset is a solution to every software-related problem. It wipes everything down and it brings the device to the state it was in when it left the factory. 

To reset your device:

1. Go to Settings -> Tap on General -> Select Reset
   
      
   
   
   
2. Tap on Erase All Content and Settings -> Erase iPhone (iPad/iPod) -> Enter the password of the synchronized account -> Erase
   
   

   
   
   

Also, you can reset it via iTunes: 

Connect your device to your computer using the cable that came with it -> Select your iPhone, iPad, or iPod when it appears in iTunes -> In the Summary panel, click Restore iPhone... -> Click Restore again to confirm

1. Have iTunes running on your computer before you begin this procedure
   
   
2. Press and hold the Power (Sleep/Wake) button and move the slider to turn it off (or press and hold the power and home buttons at the same time for a few seconds if the touch screen is unresponsive)
   
   
3. Connect your device via the USB cable to the computer - Press and hold the Power (Sleep/Wake) button and the Home button at the same time and relese the Power (Sleep/Wake) button but keep holding the home button until you receive a notification on your computer
   
   
4. Once iTunes informs you that it has detected a device in recovery mode, click the Restore button and iTunes will restore the  device’s operating system.

Note: Connect your device to the charger when performing hard reset to avoid sudden shutdowns, which can inflict an irreversible damage to your device. If you use iTunes on a laptop, plug the laptop's AC adapter in an power outlet.

Also, if you cannot access the recovery mode menu, maybe the power ON/OFF button or the Home buton are not working properly (In this case, take it to a repair store).

Make sure that your phone is turned on.

1. Press and hold the Volume down (-) and the Power (Sleep/Wake) buttons at the same time
   
   
2. Once your phone vibrates release them

Note: Do not touch the screen during the process (not even when the slide down to power off prompt appears)