Some, but not all, Arduino kits include a activation code for online content access, or software licenses such as Matlab for the Engineering kit, or the 12 months free Cloud Maker plan included with the Oplà IoT kit.
The activation code along with activation activation can be found inside the kit. Both will typically be visible when the box is opened, on the inside of the lid or on the cardboard material.
Note: The Arduino Starter Kit Multi-Language doesn’t need to be activated, and does not come with an activation code.