Transaction variants allow you to preset values for fields in a transaction, set field attributes, or hide entire screens.
You can create transaction variants in the SAP Reference IMG.
Professional User Transactions are the standard transactions executed in the SAP system. An Easy Web Transaction is an ITS-based transaction, which can be executed only in the SAP GUI for HTML. You need to refer to an ITS service in order to use it.
The SAP GUI settings do not affect the transaction itself; they only inform the user what software is needed to start the transaction: SAP GUI for Windows, SAP GUI for Java or only the browser (SAP GUI for HTML).
You can use the newly created transaction code to start a special variant of the transaction.