If we create SharePoint Content Database High Availability, is anything to be done from SharePoint Side?

First, a very important point is that you need to verify your SQL Server version compatibility with the version of SharePoint you will be deploying.

Second, Some SharePoint Server databases do not support SQL Server Always On Availability Groups.

Third, after you finish all your SQL server configuration, you need to go to the "Specify Configuration Database Settings page", in the Database server box, type AGListener as the name of the computer that is running SQL Server with the required port, etc.

Finally, To finalize setup of Always On for a SharePoint Server farm, add the SharePoint databases to the availability group and synchronize secondary replicas to the primary replica.

You can check for more details in Step 8 in this Tutorial.

Further details you might find it Here

I hope this would help.

As a supplement, make sure the SharPoint databases that are supported for use with a SQL Server Always On Availability Group,for more information, see:

https://docs.microsoft.com/en-us/sharepoint/administration/supported-high-availability-and-disaster-recovery-options-for-sharepoint-databas

After that, we can use failover tests to validate the Always On installation, please refer to:

https://docs.microsoft.com/en-us/sharepoint/administration/configure-an-alwayson-availability-group#use-failover-tests-to-validate-the-always-on-installation