To take a screenshot on your iPhone or iPad, follow the steps below:
1. Hold down the Sleep/Wake button and immediately press and release the Home button
Note:
The Sleep/Wake button is that isolated button which is either at the top (e.g. iPhone 5, 5s, SE) or on the right side (e.g. iPhone 7, 8, X).
2. The screen flashes white. Your device captures the entire screen and saves it as a photo. You can find the screenshot on your Photos app.
You will then be able to attach it on an e-mail or upload it onto a website.