Hi Hema,
Thank you for posting your query to Microsoft Q&A!
Can you confirm you have local admin on that device and it is not already joined to an on-prem domain?
If its joined to an on-prem domain you will need to configure hybrid join - https://learn.microsoft.com/en-us/entra/identity/devices/hybrid-join-planThere is also another thread here on the issue with some suggested workarounds - https://learn.microsoft.com/en-us/answers/questions/31471/why-is-the-joining-an-azure-ad-option-missing
Let me know if you have any further queries, I would be happy to help.
Please "Accept the answer" if the information helped you. This will help us and others in the community as well.
Kind Regards,
Donal