Hi Irosh Prasad,
Azure Virtual Desktop (AVD) currently does not support external identities, including B2B guest accounts.
This limitation has been confirmed by Microsoft documentation.
Please refer this document:
https://learn.microsoft.com/en-us/azure/virtual-desktop/licensing#internal-and-external-commercial-purposes
If you have any further queries, let me know. If the information is helpful, please click on Upvote.
Thank you.