can someone explain this?

First can you tell me please what are the most popular banks in america. Secondly how does Swift code and IBAN number work,also I understand these are for international bank transfers,say if I want to use these whilst I am in America to transfer money to my UK debit card,do I need the swift code and IBAN number and alse reference number(16 digit number) would appreciate someone who has experience in this,many thanks

Popular banks include Wells Fargo, Bank of America, and Chase. I live in the South, so if other regions of the US it may be different.

An IBAN number is something added to the bank routing information with international banking transactions. Not used much by US Banks, but could come into play if xfering money overseas. Swift code are similar and used in some international wiring scenarios.

When wiring funds to a debit card, these cards are tied to an account and a bank. You'll need routing information for that account including any international routing codes. If the card allows wires, you should be able to get domestic and international wiring instructions. I used Chase Bank and I can wire funds online, from my phone.