can you please (do something)

This is a polite and slightly formal way to ask someone to do something when talking to a stranger.

Sir, can you please move to the side and let these other customers through?

With a closer friend or acquaintance, it's more friendly to ask "Could you ___?":

Could you pass me the salt?

swipe (a card)

To "swipe" means to make a sliding motion. When you "swipe" a credit card, debit card, or some other kind of card, you slide the card through a machine that reads the information on it.

There are also other machines that you "dip" a card into. This is the type that you put your card into and then pull it back out.

a PIN number

"PIN" is an acronym which stands for Personal Identification Number. It's similar to a password, but shorter and made up of only numbers.

Technically you don't need to say "PIN number" because "number" is already included in the letters "P-I-N". But people often say it anyway.

enter (something in a form)

When you're filling out a form, you "enter" information:

Please enter your credit card number.

I entered my email address and clicked "Submit" but nothing happened.