A MATLAB activation key is a unique code used to activate a MATLAB license. It is required to unlock the full features of the software and use it without limitations. The activation key is tied to a specific MATLAB release, in this case, R2019a.
If your workstation lacks internet access, you can download a license file from the MathWorks License Center using another device and manually upload it during the activation process. matlab+r2019a+activation+key+top