The onion address
The we the north market onion ends in .onion, is 56 characters long before that ending and opens only through Tor.
Reference pages
Sites like this one live on the ordinary web. They can list and explain the onion address, but they are not the market.
Why the difference matters
A regular website that asks you to log in to WeTheNorth is impersonating the service, because the real login lives behind the onion address.
Keep them apart
Use reference pages to find and check the address, then do everything else in Tor Browser on the onion itself.
The WeTheNorth onion is the service; ordinary web pages are only references to it.