To use the trial version, you don't need a product key. Simply download and install the software, and you'll be prompted to activate it. During the installation process, you'll have the option to try the software for free.
You're looking for a trial product key for SAP Crystal Reports 2016. Here are some details: sap crystal reports 2016 trial product key
If you want to purchase the software or need a product key for other reasons, you can contact SAP or an authorized reseller. They can provide you with a product key or more information on purchasing options. To use the trial version, you don't need a product key