A family of Microsoft word processing software products for creating web, email, and print documents.
In a Word document, the headers and footers of each section are stored in the section break at the end of the section. There is no way to copy one or a few pages of a document that includes the headers and footers, unless you include that ending section break. (And if there are no explicit section breaks, then the paragraph at the end of the document contains that information.)
Probably the easiest way to extract a few groups of pages from the original document is to start by making a copy of the original and saving it with a different file name (or in a different folder, if the file must keep the same name). Open that copy in Word, and delete the pages that aren't needed -- just click at the beginning of a part to be deleted, use the scroll bar to get to the end of that part, press Shift while clicking at the end, and pressing the Delete key. Repeat for the other parts that should be removed.
As you're doing this, be careful not to delete the section break that comes after a part that you're keeping. For example, if you're keeping pages 46 to 51, and the section that contains those pages ends on page 56, then you need to delete pages 52 to 56 but not the section break at the end of page 56. That will make sure the headers and footers remain what they were in the original document.
The other thing you need to do, in each part that you're keeping, is to set the starting page number of the section to where that part started in the original document. That is, if you deleted everything from pages 1 through 45, what was page 46 is now automatically numbered as page 1. You need to open the header on that page, click the Page Number button on the Header & Footer Tools tab of the ribbon, and click Format Page Numbers. In the dialog that opens, click in the Start At box and type the number that the first page of that part should have -- in this case, 46 -- and click OK.
If you need to keep two separate pieces from the same original section, but remove pages from between them, then you have to insert a new Next Page section break in place of the removed pages. It will automatically inherit the header and footer from the original section, and you can separately set the starting page number for each new section.