How to delete guest records and also how to activate delete record option for registered users

illusioninfotech 1. I posted some records as guest but now i cant delete them, i cant find any delete option of front end.

As SuperAdmin/Moderator you should be able to manage all records in frontend.
Make sure you have set the global Moderator in Backend -> Cobalt -> Configuration -> General Settings.
Apart from that, you can set other users as moderators in frontend.

I am Record List: default template. Can you please let me know to delete them.

If you hover over the record item/row, you should see the contextual control menu. Hence a small cog icon and dropdown menu. It includes the delete action.

2. Also, How to enable option for Registered Users to delete their records on the record list page?

Check your Type -> Form tab -> Properties (see parameters for edit, delete, prolong and hide)
Also check tab Submission Parameters, if the defaults suit your needs.

Hope this helps.