Use the following code:
var document = new Document("input.docx");
for (int Page = 0; Page < document.PageCount; Page++)
{
Document extractedPage = document.ExtractPages(Page, 1); // startindex and count
string …...for (int page = 0; page < document.PageCount; page++) { Document...extractedPage = document.ExtractPages(page, 1); // startindex and count...