Hello @Mohammed Thahif BK
Welcome to Microsoft Q&A Platform,
You have to reach out to Fortinet support:
https://www.fortinet.com/blog/business-and-technology/fortigate-vm-first-ngfw-and-secure-sd-wan-integration-in-microsoft-azure-virtual-wan
https://learn.microsoft.com/en-us/azure/virtual-wan/about-nva-hub#basic-use-cases
I hope this helps!
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