Explanation
Scenario:
Customers can select a meal when they make a reservation and can save the meal choices as a customer preference.
The company offers two types of meals: standard and vegetarian. Meal types can be temporarily unavailable. The airline is considering offering other meal types, such as gluten-free and low-sodium options.
In PowerApps Option set is one of the field types you can use in your Entity. The information type that Option Set stores is a list of text values. And here comes the Option Set advantage - once you define its text values you can centrally managed it.
Example:

Reference:
https://michalguzowski.pl/how-to-work-with-option-set-in-powerapps/