Creating an Application 
In the menu bar, choose
In the Object Creation dialog box that appears, enter Z_Tax_Calculations in the Name field. Also, provide a short text and a text. Although both fields are optional, providing texts is always recommended for easier identification and documentation.
Choose System as the storage type and select the Create Local Application check box.
$TMP appears in the Development Package field. This is the package placeholder used for local development objects.
Choose Create and navigate to object.
The application opens in the Object Manager panel.
Save and activate the application.
Note
Although activating the application at this point in time is not mandatory, it is still recommended because only with an active application it is possible to activate the objects contained in that application.