This software is proprietary and requires a valid Cisco DNA License or Support Contract (SNTC) to download legally. It is not open-source freeware. To obtain the file, you generally have two official paths:
Cisco strictly controls the distribution of SD-WAN software images. There are no public, direct download links for production-ready QCOW2 files due to licensing and export control regulations. Step-by-Step Download Path viptelaedge1923genericx8664qcow2 download link