In a multi-line text field, the top margin (padding) seem excessive and does not match the margin seen in single line fields. The following graphics illustrates this issue:
All lines displayed in the multi-line field, notice the extra margin/padding at the top of the field. The font used does not seem to matter. This example uses Consolas (a fixed size font - like Courier)
Moving up the bottom of the field does not change the top margin.
Calibri displays the same issue (commonly used in Microsoft products)
After much searching there seemed to be at one time a 'Paragaph' tab in the form field properties dialog. No more.
Thank you for your time.
It's still there, but not under Properties. You have to set the field as having Rich Text Formatting (that is done via Properties, under the Options tab), then click into it and press Ctrl+E. A floating toolbar will open. Select the text and click the More button in that toolbar and there you'll find the Paragraph tab with this setting. However, this setting doesn't "stick", so if you clear the text in the field and then enter something else into it that setting will no longer be applied.
This doesn't actually answer the question though.
You can edit the text properties as described above, but there is no way to actually remove the padding, even if the properties would stick once the text is changed. The screenshot here shows that even with all of the paragraph options set to '0' (which was what it defaulted to), the padding still exists and there is no way to change it. I wish Adobe would fix this - I found examples of this going back to 2016, and it's such a simple thing.
No it's not a simple thing. And it's not an Adobe Problem. This is a feature that can only be defined in the PDF Specification, and it doesn't, so it's up to the developers who make the PDF viewers to decide how to do it. Which means that if Adobe decided to change it, then they'd be out of sync with everyone else. But if the spec changes, then anyone who doesn't follow the spec is out of sync.
I'd strongly suggest you create a proposal and submit it too the ISO 32000 steering committee. See how that goes.
++ Adding to the topic,
In that case this is what I would do: