Custom Paper Settings

If the paper size you require is not under [Paper Size], you can register a customized paper size.
From the [File] menu of the application, select [Print].
Select [Manage Custom Sizes] from [Paper Size].
Click [+] → double-click [Untitled] → enter a name for custom paper size.
Set the paper size and margins → click [OK].
You can select the registered paper size from [Paper Size] in the [Print] or [Page Setup] dialog box.
You can also set custom paper sizes from the dialog box displayed when you select [Page Setup] from the [File] menu of an application.
If the custom paper size you have set is not displayed in [Print] dialog box > [Paper Handling] preference pane > [Destination Paper Size], you cannot print using that paper size. You need to change the paper size.