To say "I'll pay" or "I'll take care of the bill" in casual English, you can say "I got this" or "I'll handle it." If you are in a restaurant, you can also say "Can I have the check, please?" or "Can I pay the bill now?" If you are paying with a credit card, you can say "Can I put this on my card?" or "I'd like to pay with my card, please." It's also common to ask someone else if they would like to split the bill, in which case you can say "Do you want to split the bill?" or "Do you want to go Dutch?"
