The gifted subscription rewards control what commands, if any, are reward to users when they gift subscriptions to your channel.
To enable gifted subscription rewards you must toggle them on.
You can see if gifted subscription rewards are currently enabled by the overlay icons in the navigation menu and window title bar. When enabled the overlay icon is shown, e.g.
When disabled, the icon will be used instead.
The general tab of the gifted subscription reward screen controls what if anything is rewarded when a user gift one or more subscriptions to other users.
The notification tab of the gifted subscription reward screen controls what if anything is sent to chat when you get a gifted subscription.