Assuming you would like to insert a PDF as one page:
1. Go to File > Place and select your PDF. Check the Show Import Options box.
2. In the Place PDF dialog box, click on All Pages in the Range section. Then click OK.
3. The pages of your PDF will show up as separate images in your document window. If you need to edit any of them, double-click on the image to open it in Acrobat DC Pro. Otherwise, just drag each image into place on your InDesign layout pages.