how do I post url feed

You will need to be logged in to the iTunes Store. Enter this URL in your browser:

https://phobos.apple.com/WebObjects/MZFinance.woa/wa/publishPodcast.

(There have been cases of people getting error messages doing this: if so, try

https://buy.itunes.apple.com/WebObjects/MZFinance.woa/wa/publishPodcast.)

This will open iTunes to a pane where you can submit the podcast: again, enter the feed URL, not the URL of the media file. iTunes does not store your media, it just uses the contents of the feed file to provide the details and access on the iTunes Store. (None of this will cost you anything).

It may take some days before the podcast is accepted, since each new podcast has to be checked to make sure there is no unacceptable content.

When your podcast is accepted, iTunes will give you a URL which will open iTunes to your podcast. You will also eventually be able to search on its title, though this can take some time to become available

You won't see any of your details in iTunes until the podcast is accepted (which can take a couple of weeks or so) but if any of the details are wrong you should correct them in the appropriate places in Podcast Maker.