How can I get my icon back on my Opening screen

Slide to the last screen “App Library”. Type “messages” in the search bar at the top. Find messages icon and click on it. Select add to Home Screen. Go back to your Home Screen and you can move the icon back where you want it by putting your finger on it until all icons begin to wiggle. Now touch and keep your finger on the Messages icon and drag it back down where you want it and let go.

Perhaps you’re referring to a widget, if so hold your finger on your Home Screen until all icons are wiggling. Now depress the + at the top of your screen. Search through the available widgets and select the one you want.

What icon might that be? On what model iPhone?