How can I prevent users from deleting opportunities?

Smart actions make frequently used tasks, such as creating, editing, or deleting records, easily accessible because they're always available from the same place on a page, such as from the Workspace list page or in the Action Bar.

You can use the Smart Actions page in Application Composer to enable or disable actions. Or, you can allow or restrict access to specific actions through privileges that are granted for different roles. For example, the delete action for opportunities has the privilege MOO_DELETE_OPPORTUNITY_PRIV associated with it. If a user doesn't have this privilege, or if the privilege is revoked for the necessary role, then the delete smart action wont be available to that user.