Olympus and OM System lenses have a distinctive way of toggling between manual focus and autofocus on their lenses.
Olympus is now OM System
In 2020-21, the photography business of iconic camera brand Olympus was spun off and sold. The core remaining Olympus brand is focusing on medical and scientific products. The camera and photography side was then rebranded as OM System, with the first cameras and lenses under that brand coming out at the end of 2021.
If you’ve ever found that your Olympus M.Zuiko Digital ED 12-100mm f/4 IS PRO zoom lens seems stuck on manual focus, there’s a good chance you’ve run into this issue (especially if you’ve found this page and are here reading this!)
Unlike some other brand lenses, there’s no AF/MF switch on the side of the lens. And there’s no menu item in the camera’s settings.
Instead, on this lens, what you want to look for is the ring on the lens barrel that’s farthest from the camera body. It also happens to be the focus ring when you’re using manual focus.
But rather than turning it, you want to slide it forward or back gently. You’ll feel it click–that’s the way to toggle between manual focus and autofocus.
When it’s in manual focus mode, you’ll be able to see the distance measurement scale.

When it’s in autofocus mode, that distance scale will be covered.

So it’s not complicated or difficult, but it’s also not necessarily intuitive if you’re more familiar with other lenses.