You can simply reset your Android to factory settings through "Backup and Reset" feature available in settings.
However, this won't work if your phone has got hanged or you have forgotten the password.
Here is a Quick reference to hard reset your phone:
- Power off your phone (If the phone is hanged, directly perform the next step)
- Press and hold Volume Down and Power button to enter recovery mode. (Old phone might use home button as well)
- After the Android logo, you'll be presented by a menu.
- Select "Wipe Data/Factory reset" from the menu.
- Press the Power button to confirm.
- Scroll to "Yes" and confirm with Power button.
- This will start the Reset Process.
You can see the video to perform hard reset here:
You can see detailed specs of the phone here: Vivo S1