To obtain the installation media, follow these steps via the Palo Alto Networks Customer Support Portal :
Locate the desired software version (e.g., 10.1 or 11.0) and click Palo Alto Networks LIVEcommunity 2. Requesting a Free 30-Day Trial If you do not have a paid license, you can request a 30-day trial image directly from Palo Alto Networks. Palo Alto Networks : Visit the VM-Series Free Trial page
The only secure and authorized way to obtain a Palo Alto ISO or VM image is through the Palo Alto Networks Customer Support Portal. How to Download Palo Alto Networks VM-Series Images