Navigate to the Microchip Software Licensing Site. You will need a free Microchip account (no purchase required).
The free Silver license is designed for entry-level development and evaluating Microchip's low-power FPGAs. Licensing - Microchip Technology microchip libero license free
Alternatively, if you have a supported device, the software may automatically operate in free mode without explicit license entry. Navigate to the Microchip Software Licensing Site