But, if you bought the regular iPhone 11, and not one of the Pro models, you have one more accessory to buy.
The iPhone 11 supports Apple's fast charging, which can give you up to a 50% charge in just 30 minutes. But, the phone ships with Apple's standard 5-watt charger, which takes hours to give it a full charge. Only the iPhone 11 Pro and the iPhone 11 Pro Max ship with the new, faster 18-watt charger in the box.
So if you bought the regular iPhone 11, you should buy Apple's new 18-watt charger separately to replace the 5-watt charger in your iPhone 11 box. It costs $30 and is available from Apple Stores and on Apple's website.
Other manufacturers make the chargers, and you can find them for cheaper, but it's safer to buy Apple's official one so that you don't have to worry about battery damage if you accidentally buy one from an unreliable accessory maker.
You'll also need a USB-C to Lightning cable, since the charger has a USB-C connector on it. Apple sells a 1-meter cable for $19, but I recommend the $35 2-meter cable that gives you a bit more length.
It's well worth the money, as you'll spend more time using your new iPhone instead of waiting for it to charge.