A phishing email or text appears to come from a trusted organisation (a bank, courier, colleague or supplier) and asks you to click a link, open a file or "verify your account". The link leads to a fake site that looks like the real one.
Warning signs: pressure to act fast ("blocked within 24 hours"), an odd sender address, a request to "change" bank details. When in doubt, verify through another channel, such as a phone call.
Example
An accountant gets an email from a "supplier" saying their bank account has changed. A phone call to the supplier confirms the email is fake.