Hello Muhammad Irfan Khalid,
Thanks for your question
For issues with phone validation, see: https://learn.microsoft.com/en-us/azure/cost-management-billing/troubleshoot-subscription/troubleshoot-azure-sign-up#identity-verification-by-phone
I have seen this issue a few times, some other users solved it by attempting signup using their mobile phone. I would recommend you try signing up on your phone
You can mark it 'Accept Answer' and 'Upvote' if this helped you
Regards,
Abiola