Urgent Help Needed with Margin Notes conversion to MS Word

[Kitsune]

Hi everyone, I've just started proofreading students' essays online for a fee. I've been learning as I go along and I am finding the ability to write notes in boxes in the margins very useful. Even when I save as a Word document, the boxes still have little arrows you can click on to get a drop-down menu which gives you the option to delete one or all of the boxes.

My client today (only the second one I've worked with) has been telling me that he can't get rid of the boxes. I sent the document to my husband at work and he sent me a screen shot showing the boxes in pink, with no way to access a drop-down menu. So how would a MS Word user get rid of them? Does anyone know why the drop-down menu seems to disappear once I have emailed the document and someone is opening it on another computer in Word?

Any help would be appreciated, thanks.