Trust is key to any relationship. Cybercriminals count on that when they spoof a webpage. Websites mimicking a trusted business increase the odds visitors will enter credentials or payment information — especially if the login window also closely resembles the real one.
Scammers create URLs containing subtle misspellings (vectrabank.com vs. vectorbank.com) or using unusual extensions (.cam vs. .com). They also add phrases to legitimate domains (support-vectrabank.com or vectrabank.com[info]) to lure you in. From there, it's just a matter of continuing to make the phony website look like the real deal.
Whether you're looking at a webpage or a login window, examine the URL carefully.