Online payment with crypto through withdrawal

I have a noob question since i dont use crypto very much. I only have ETH on stake and I want to buy a phone from tradingshenzhen which accepts crypto but I dont know much about crypto payments, how they work. At checkout my guess is they give me an address. My question is, to make the payment, is it as easy as withdrawing the ETHereum amount to the wallet address they give me, or do I have to use some specific website and use a "Send" feature like binance or kraken. Thanks in advance for the help