Copy Caption from RAW to JPEG?

I shoot in RAW + JPEG.

This is a choice which has a number of consequences. There are reasons to do so:

- because you are in a hurry to share jpegs before having the time to convert and edit

- you really like the jpeg rendition of your camera

- you want a comparison to learn more how to convert your raw files.

I don't think I am alone, I have seen many users  reverting to only shooting raw. For me raw+jpeg is a useless workflow once I know how to export automatically jpeg versions if I am in a hurry and I no longer need the jpeg version of my camera. My normal workflow is to edit in ACR, even jpegs and to nearly always create a full size jpeg version set.

Photoshop Elements Organizer 2020 automatically stacks the RAW photo on top of the JPEG, which is wonderful.

Not for me. I am not alone, for many users, what should be "on top" is the version set, not the underlying 'negative'.

If you shoot raw + jpeg with the raw on top:

- you slow down the navigation in the organizer browsing space

- you lose the ability to simply 'flatten' the set when you think the raw negative is no longer needed.

- I imagine you no longer need the original jpeg after creating a version set with jpeg or tiff/psd. Not easy to delete the original jpeg in the stack and the version set.

I understand the need to assign the same caption in a collapsed stack or a version set (like keywords), but I also understand that if you want to create several version sets, you may want a distinct caption for each version.

I can't help you with a method for copying the captions.  But, for the future, you can use the View>Expand All Stacks command to expose both Jpeg+raw files.  You should then be able to add a caption to all selections.