Where to buy ETH and transfer instantly?

Hello there, could you please enlighten me on a pressing matter? I'm in the market to purchase some Ethereum, or ETH as it's commonly known. Now, the catch is, I need to be able to transfer it instantly. Could you guide me on where exactly I could buy ETH and have it transferred without any delay? Are there any reliable platforms or exchanges that offer such a service? Also, would you mind sharing any safety measures I should take while making this transaction? It's my first time doing this, so any advice would be greatly appreciated. Thank you in advance for your assistance.