Not sure where you are located, but in Sweden, Klarna at the start (if I remember it correctly) only needed your 'personnummer'(social security number) to process payments.
Now I think they manage to track your devices so I only have to enter my postal code, and then I just click purchase, and it's all done.
They used to use really weird/dark patterns, to make you forget to pay and then pay huge fees to Klarna.
Nowadays as I've configured Klarna, it just subtracts the amount from my bank account, hassle free, and I don't have to do a bunch of reserach wether or not the website is credible.
Somewhat like Paypal, but smooother.