Hello Navin kumar,
I hope you are doing great,
You can enable it here:
Choose Configuration > Clientless SSL VPN Access > Connection Profiles>Advanced>Clientless SSL VPN panel.
That option above is to create an alias on the URL, but for the group drop-down it would be the above option "Alias", you click add and type the name you want.
Make sure that on the "Allow users to select connection, identified by alias, in table above at login page"
Then apply the config and retry the connection and disconnect and it should be showing. Now if you have multiple Remote Access connections you have to create an Alias for all of them or a URL group. Below I will provide a link which has the official steps:
https://www.cisco.com/c/en/us/support/docs/security/asa-5500-x-series-next-generation-firewalls/98580-enable-group-dropdown.html#maintask1
Keep me posted,
Please qualify all of the helpful answers!
David Castro,