Understanding PDF Metadata

Are the Extended Properties in the metadata pane something that PDF’s have with where ever they are or just in Opus? If you edit the Extended Properties, it and take to another computer with Opus will it have the metadata? And what about a computer without Opus? I am looking for data that will be with the PDF’s for its lifetime. I see there is also the subject area in the Document Properties could that be a better choice if I want to make the Metadata permanent? Thanks

Which fields, specifically?

A quick way to test where things are saved is to copy the PDF, then save a change to a field, and compare the file with the original using a binary comparison tool (e.g. WinMerge is free; "fc" is built into Windows if you don't mind using the command line).

Good, I see what you mean by using the technique you show. I see the Description of Extended Properties is not copied over. Can I tell Opus to do a copy of a file with this Metadata? Would I need to develop a custom script to accomplish this? I already plan to create a script that will open a larger dialog to type this Description in it. Thanks

Have a look under Preferences / File Operations / Copy Attributes.

pctechtv: some suggestions, depending on what exactly you want to do with the PDFs.
The best way, of course, is to place the metadata inside the PDF, and the official way to do that is using Acrobat Pro DC;
Get the complete PDF solution US$14.99/month
-this gives you complete control (inserting, editing, saving PDF/XMP metadata), but at an ongoing cost.

Less expensive is PDF Architect at:
http://www.pdfforge.org/pdfarchitect/modules
Modules included in this package: Convert, Edit, Insert US$59.00 one-time cost.
Note: you can use the PdfCreator for free, and it will allow you to set some metadata as you print-to/create the PDF.

More technical, but free, open-source is: ExifTool by Phil Harvey
http://www.sno.phy.queensu.ca/~phil/exiftool/
Read, Write and Edit all Meta Information. Windows, Mac OSX executables available.
ExifTool is a "command-line" utility. That means, there's no Graphic User Interface (GUI), so all work must be done by typing commands inside "Command Prompt"
You could make DOpus buttons to do things, but I found this easier and more flexible: ExifToolGUI
http://u88.n24.queensu.ca/~bogdan/
a very useful GUI graphical front-end to ExifTool
with these you can add/edit the important metadata in PDFs, like (these are ExifTool commands):
Set PDF metadata=-PDF:Title="my Title" -PDF:Subject="my Subject" -PDF:Author="myAuthor"
Set PDF mod.date to value=-ModifyDate="2015:07:01T12:00:00-07:00"
update PDF file dates using XMP dates=-FileCreateDate<XMP:CreateDate -FileModifyDate<XMP:ModifyDate

Since I don't know of any way in DOpus to view/edit the internal XMP in PDFs, I have created a button to call ExifToolGUI for the current folder, and operate on the PDFs that way.

Maybe Leo knows a way to use the powerful scripting in DOpus to edit the internal XMP in PDFs. Or, maybe PDF metadata view/edit is a feature coming in DOpus12?