how to edit draft email message

On my iMac I double click on the draft to open it in a separate window where it's editable.

I did move the message from the Drafts folder "On My Mac" to the Drafts folder in my IMAP account (so I could see it on my iPad). This may be the cause of my problem. I'll try with a draft left in the On My Mac.

I see. Unfortunately I don't use Mail enough to troubleshoot your issue. I can't reproduce the problem on my devices. If I create a draft on one of my Macs, I can access it on my iPads and iPhone, and vice versa.

Hopefully someone can figure it out for you. You could always contact Apple: Get Support

I just double click on it and it becomes "editable".

If it still won't allow you to edit, you could copy the whole message into another text editing software (such as Notes) and write there, then paste everything back into the email draft to save it.

I tried that with TextEdit. Also I tried copying everything into a new email, and editing it. Both solutions are awkward workarounds - it should just work.

Did you move the draft to a different folder than the Draft folder? Works fine here just re-opening the draft.

Hopefully that will resolve it.

Working with a draft stored "On my Mac" seems to have solved the problem. I can come back and edit this draft further. However, it is not accessible form my iPad.