This would be a calculated page field.

First, these fields must be constructed by hand, you can't just insert them. Second, the braces { } or field delimiters must be entered in pairs using Ctrl+F9. This is something that can be done. It is straightforward, but there are a lot of steps in the setup.

The basic fields are { PAGE } and { NUMPAGES }. I will first show you the field you need. Then I will take you step-by-step on how to construct the field. Finally, I will take you through the steps to put it in your footer. Then I will show you how to save it as a building block AutoText. Finally, if you want, I will show you how to make it a Footer Building Block.

I will post this in pieces.

Start, in your document, by typing PAGE or page or Page. Select the word you typed and press Ctrl+F9. Then press F9.

While I'm typing, you might want to look at How to control the page numbering in a Word document.