Never worked with MS WORD that much.

This is a good one.

Insert Text Box on top of an image in MS Word document.

Past the image inside the MS Word document.

INSERT menu -> Text Box -> Draw Textbox

Click somewhere in the image

Now this appears:

Click the down arrow to find at the bottom the by Callouts this red one:

Click inside the image in the doc, you got this one:

Right mouse click on the border of the text box, you then open the tool pallet at right side.
Here you can specify which color to use to fill the text rectangle, the thickness of the line etc.

Type in some text in the Text box, click menu HOME, you can center align the text, set the font and size of the text. That’s it. And when dragging the text box, the arrow line will go together.