: You can buy a MATLAB license directly from MathWorks. They offer various products and toolboxes, so you can choose what suits your needs best.
: During installation, you'll be prompted to activate your license. This usually involves entering your MathWorks account credentials or a license file provided with your purchase.
The tale of a software seeker...
If cost is a concern, consider these legal options:
For help with obtaining or managing your MATLAB license, I recommend: