How can one reduce Microsoft Outlook's background mobile data usage?

See Microsoft's offical website for the full details: https://answers.microsoft.com/en-us/msoffice/forum/all/outlook-data-hog/a88b5e3f-2982-4558-a190-1afa93044e1f

You can do a number of things to reduce background data usage:

1. Turn off mobile data when connected to Wifi.
   This may sound strange, but apparently Outlook sometimes still uses mobile data, even when connected to a stable Wifi network.


2. Turning off the "Sync" feature


3. If there is the feature, set a data limit on Outlook.
   This will prevent it from eating up your data when you arn't using it.