To take a screenshot on an iPad, simply press and hold the Sleep/Wake button on the top of your iPad. Then, press and release the Home button. You should see a flash and hear a camera shutter sound, indicating that a screenshot has been taken. The screenshot will be automatically saved to your Photos app.
You can also take a screenshot by using the AssistiveTouch feature. To do this, go to Settings > General > Accessibility > AssistiveTouch and turn on the AssistiveTouch switch. This will add a white button to your screen that you can tap to access various options. To take a screenshot, tap the AssistiveTouch button, then tap Device > More > Screenshot.