how can i reset my ipad 4?

1. Open iTunes on your Mac or PC.
2. Connect your iPhone, iPad, or iPod to your computer with the cable that came with your device.
3. If a message asks for your device passcode or to Trust This Computer, follow the onscreen steps. If you forgot your passcode, get help.
4. Select your iPhone, iPad, or iPod when it appears in iTunes.
5. In the Summary panel, click Restore [device].
6. Click Restore again to confirm. Then iTunes erases your device and installs the latest iOS or iPod software.
7. After your device restores to factory settings, it restarts. Now you can set it up as new.

Here are the instructions in the link below to reset to factory settings 🙂

Use iTunes on your Mac or PC to restore your iPhone, iPad, or iPod to factory settings - Apple Support

Depending on exactly what you want to do:

Restart or force restart: https://support.apple.com/en-us/HT201559

or

Settings > General > Reset