AlwaysOn High Availability doesn't work , can't activate it

You need Enterprise edition for fully functional Always ON AG and a minimum Standard edition to use the basic Always On AG. Express edition of SQL Server does not supports Availability Groups

If you read the message above in your screenshot, its very clear that it requires enterprise edition in order to enable always on availability group, even for basic AG you need to have standard edition of Sql server. This also requires WSFC hotfix to be installed on the operating system. It doesn't work on SQL server express edition.

Please read the prerequisite before doing set-up of always on availability:

https://docs.microsoft.com/en-us/sql/database-engine/availability-groups/windows/prereqs-restrictions-recommendations-always-on-availability?view=sql-server-ver15

https://docs.microsoft.com/en-us/sql/sql-server/install/hardware-and-software-requirements-for-installing-sql-server?view=sql-server-ver15

https://docs.microsoft.com/en-us/sql/sql-server/failover-clusters/windows/windows-server-failover-clustering-wsfc-with-sql-server?view=sql-server-ver15

Once you meet the prerequisite, please follow step by step instructions and coomplete the setup. you may refer this article written by Mr. Brent Ozar.