The title of this article does not accurately reflect the real picture. You can hardly earn bitcoins immediately (they are too expensive nowadays), only if you will endlessly click on the buttons of the faucets and get satoshis – smaller coins than bitcoin.
If you already have your bitcoin wallet number you can start earning cryptocurrency.
There are a lot of faucets in the web, but many of them are just scams, so it it hard to find real and safe. here is the list of good faucets, checked by me personally for a long time.
Multi (many different coins)-faucets
Some more useful links