@Lasitha Dissanayake ,
Thank you for reaching out to the Microsoft Q&A platform. Happy to answer your question.
There are several license plans available for the Azure AD service, including Azure AD Free, Azure AD Premium P1, and Azure AD Premium P2. You have to purchase licenses at the user level, and the price will vary based on the plan. For more details please visit - https://azure.microsoft.com/en-us/pricing/details/active-directory/
You can assign the license to a user or to a group. The group is added to the list of licensed groups and all of the members have access to the included Azure AD services. For more details, please visit - https://learn.microsoft.com/en-us/azure/active-directory/fundamentals/license-users-groups#available-license-plans
Azure Active Directory premium editions come with advanced identity protection and privileged identity management capabilities. If your requirement is to create groups and assign groups to enterprise applications, will the free license suffice your requirement?
I hope I answered your question. If not, please give more details in the comments section, I will try to get back as soon as possible. Thanks. Please "Accept as Answer" and Upvote if any of the above helped so that, it can help others in the community looking for remediation for similar issues.