Why are there no archives under the organizer section in xcode?

Adding to Matias Jurfest answer, in Xcode 12, you would need to

Set "Any iOS Device" as the selected device (top left corner near the scheme) instead of a simulator device.

If you've already created an archive by going to Product > Archive. I would try restarting Xcode. That might not be helpful, but that's where I would start, let me know.

To build your archive you need to:

1 - Set "Generic iOS Device" as the selected device (top left corner near the scheme) instead of a simulator device.

2 - Click on "Product" on the top bar, and then "Archive". This will start building your archive. When it finishes the Organizer will comes up and you will be able to see your archive.