https://learn.microsoft.com/en-us/dotnet/api/system.drawing.printing.printersettings.papersizecollection?view=netframework-4.8.1&redirectedfrom=MSDN
PrinterSettings.PaperSizeCollection Class (System.Drawing.Printing) | Microsoft Learn
Contains a collection of PaperSize objects.
class systemdrawingprintingmicrosoftlearn