Open the document to print.
Select [Print] on the [File] menu.
Select the printer you are using in the [Printer:] pop-up menu.
Select [Manage Custom Size] or [Custom Paper Size] in the [Paper Size:] pop-up menu.
Open the dialog box for registering custom paper size.
Click [New] or [+], and then enter the name for the original paper size.
When modifying an existing custom paper size, click the setting name. You can register multiple custom paper settings.
Specify the paper size by entering values in [Paper Size:] and [Non-Printable Area:] or [Printer Margins].
Click [OK].
Print the document using the print function in the document's native application.
Under some operating system versions, custom size paper cannot be registered unless "Any Printer" is specified as the target printer.
Due to calculation errors, the actual dimension of the custom size paper may not match the value entered by the user.