iOS currently has both "Aways" and "Only While Using" options, but the developer specifies which are available to the user. iOS 11 now forces the "Only While Using" option to be available for all location using apps.

iOS has had the permission at that granularity since iOS 8.

https://www.imore.com/how-only-allow-apps-see-your-location-...

> Keep in mind that some apps may not show all three options. This is most likely because the developer has not yet implemented the while using this app option.