There are two ways to change them. One is a relatively simple method built into iOS 18 and the other is a bit more advanced ...

The icon can also appear as a white block with the letter appearing in black. Most commonly, NFC is used to make contactless payments at terminals. Simply swiping your phone against the payment ...

Android is all about customization, but many devices still have fixed icon sizes. If they can be resized, the option is usually hard to find. Perhaps you want them bigger so you can see them ...