付款 is a separable verb (离合词) meaning 'to pay'. It can be split when adding aspect markers, duration, or measure words between 付 and 款 — for example, 付了款 ('paid the money'), 付过一次款 ('paid once'), or 付完款 ('finished paying'). You use it in contexts like paying for goods, services, or bills. Common collocations include 扫码付款 ('scan to pay') and 分期付款 ('pay in installments').