Location services / Google Location History
The only location services configurable on most devices is likely to be Google Location History. This setting allows you to specify whether Google should be allowed to store where you were at a given time, and keep a history of such locations for future use.
Google says that this information can be used help improve various services for you, such as learning what locations you regularly visit and your regular commute routes, which it may then use to show relevant information in apps such as Google Now.
The information can also be used to try and show you more relevant advertisements in apps or websites which display Google advertisements.
Delete location history
This button allows you to instruct Google to delete all location information it has already stored about you. If you are disabling location history on this page, you may also want to use this button as well if you want already stored information deleted.
For privacy reasons you may not want Google to keep a record of previous locations, and this setting allows you to turn that off.
Note that other non-Google apps that request your location may also have the ability to store your locations for future use, and if so, they may not be affected by this setting.