File Extension PM4 File Format Document (PageMaker 4.0) PM4 stands for Document (PageMaker 4.0). This was last updated in March 2012 By Margaret Rouse Browse File Extensions Alphabetically: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # Ask a Question. Find an Answer. Ask your peers a question about this file extension. Ask a Question calendar & scheduling PM400 screen to print Server 2003, NTBackup Utility, Shadowcopy Service and Network Drives.