I guess you didn't do any research before buying your new iPhone. Apple made it clear what was in the box online. And since iPhone 12, they haven't included charging plugs with iPhone or Apple Watch. Apple's way of going green is one explanation. And they know most people have a drawer full of charging plugs. If you have a previous iPhone, you can use the very same charging cable and plug you used for it. If you have a computer with USB C, you can use that. If you never owned an iPhone nor have a computer with USB C (ALL newer computers come with USB C), then you'll need to buy a charging plug if you want to charge your phone plugged in. I use the new MagSafe charging system, which is terrific. But I had to invest in MagSafe. Just like you may need to invest in something that will meet your needs for charging your phone.
The world is rapidly moving to USB C. USB A is very old technology and can't offer fast charging, like USB C can.
Finally, Samsung no longer includes charging plugs with their phones and watches, for the very same reasons.