How to Take a Screenshot on an iPhone 8 or iPhone 8 Plus

Locate your Sleep/Wake button.
Depending on the model of iPhone, your Sleep/Wake button may be at the top of your phone (older models) or on the right side of it (newer models).
To take a screenshot, simultaneously press both your Sleep/Wake and Home button, then quickly release them.
The screen will flash white, letting you know a screenshot was taken.
As with the iPhone X and later, a thumbnail of your screenshot will appear in the lower-left corner of your screen; you’ll have the option to tap the thumbnail and use Markup.
Open your Photos app to see the screenshot you just took.