Is it possible to copy and paste an entire web page into a word document?
Technically no unless you do a screen clip and paste it as an image. You do have the option of saving the web page as an HTML format, and Word CAN open those file formats. But it will likely not look exactly the same
Joe Fiduccia's answer is pretty much on target, though you can skip the save step and Ctrl+A, Ctrl+C to select and copy the entire web page, then Ctrl+P to paste it into the Word document. Whether you save or copy and paste, Microsoft Word was not particularly optimized for random modern web HTML, so, as Joe noted, you probably will not like the results. Copying the page as a image (for example with the Windows Snipping Tool) might get you what you want if the page has only static content and does not need to be edited.