how do i convert a pdf file to ipages?

No. All the so-called $$$ converter applications that claim this is possible wing it, and leave you with hours of document reformatting to come even close to what was in the original PDF. There is no product named iPages.

You can copy/paste the non-image text from a PDF document into Pages. You will be more productive doing this. If there are images in the PDF, you can open the PDF in LibreOffice Draw, select, and extract the images — to be later drag & dropped back into the Pages document.

If you are tempted to use Acrobat, consider this

Where do you get "ipages"?

Peter