Windows 11 users can join new Windows devices to Azure AD during the first-run out-of-box experience (OOBE).
Note: Windows Home Editions do not support Azure AD join. These editions can still access many of the benefits by using Azure AD registration.
For information about how complete Azure AD registration on a Windows device see the support article Register your personal device on your work or school network
You can follow steps in below article to join Windows 11 devices to Azure AD.
And to you follow-up question, you can perform Azure AD join for few users also while other users are hybrid Azure AD joined. This is possible because Azure hybrid Azure AD join is performed for devices which are joined to on-premises domain.
And Azure AD join is performed for devices which are in workgroup.
Apart from this you can follow below article to know more about Intune licensing.
Let me know if you have any further questions on this.
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