Computer Configuration > Administrative Templates > Google Chrome > Printing
Both
HKLM\Software\Policies\Google\Chrome
Overrides default printing page size. name should contain one of the listed formats or 'custom' if required paper size is not in the list. If 'custom' value is provided custom_size property should be specified. It describes the desired height and width in micrometers. Otherwise custom_size property shouldn't be specified. Policy that violates these rules is ignored. If the page size is unavailable on the printer chosen by the user this policy is ignored. See https://cloud.google.com/docs/chrome-enterprise/policies/?policy=PrintingPaperSizeDefault for more information about schema and formatting. Example value: { "custom_size": { "height": 297000, "width": 210000 }, "name": "custom" }