White box for caption over photos.

[Laura Mae22018488t2hk]

Help. 

I have searched this online, on various forums...including searching this onee, and am not finding one speck of help.  All suggestions are to right-click text box and choose edit or properties.

I don't get any of those options when right-clicking the text box.  I just want to overlay a white caption/text box over photos in my document. 

[Bernd Alheit]

Use a form text field with white background.

[Luke Jennings3]

The best option is usually to add the captions in the source document and make a new PDF, if this is not possible, and you have InDesign, place the PDF into InDesign, add captions and export to a new PDF.