In android device, you are able to turn on the service for the particular person manually. You have to click on a small button that placed in bottom right corner to enable the location for particular user. To disable it, you should turn it gray by again tapping on the button. See the screenshot below for better understanding. Be sure that if you turn the button into gray in particular chat then the location is inactive for that person only.
To permanently turn off the service, you have to click on the settings icon that located top of your app then scroll down in settings for location option. Simply uncheck it to disable the location service.