A segmented control groups a few closely related choices side by side, with each choice in its own joined section. It is like a small set of adjacent buttons that make one selected option easy to see.
For example, a calendar might let someone switch between “Day,” “Week,” and “Month” views. The control keeps those choices together because each one changes how the same information is shown.
Keep the choices short and limited in number. If there are many options or the labels are long, a menu or list may be easier to use, especially on a phone.