I'm guessing you are living someplace where there is absolutely no news of the world whatsoever.
Apple (as well as Samsung and others) quit including power adapters and headphones with iPhone about 2 and a 1/2 years ago due to the enormous glut of power adapters in the world and the problems they are causing. And thanks to the EU phone manufacturers are having to standardize on connectors. USB-C is a newer connection that does much more much faster than USB-A.
If you have an older Lightning to USB-A cable use it, it won't charge as fast but it will work. If you have USB-A connections in your mains use the same cable. Or you can buy an adapter for your mains. Otherwise buy an Anker Nano 20W USB-C power adapter for less than the Apple power adapter and use it and get fast charging and a color selection. If you have a bunch of old USB-A power adapters and they are Apple's the Apple Store will recycle them for you. If they are not Best Buy will recycle them for you. As we move forward and USB-C is the standard the next time you purchase a phone that doesn't have a power adapter (from whatever company) you will just use the power adapter you already have.