Type conversion is when you change something from one type (like a color) to another type (like a shape). It's like turning a blue ball into a red square. Sometimes, things that look different on the outside can be changed into something else on the inside.
For example, let's say you have a number "5" written down. That number is a type of data called an integer. You can change it into a different type of data, like a string, which is just a fancy way of saying a bunch of letters and symbols put together. So "5" can become "five" just by changing its type.
Why do people do type conversion, you may ask? Well, sometimes we need to use different types of data to do different things. For example, if you want to draw a picture on the computer, you might need to use numbers to make the shapes. But if you want to write a story, you would use words instead. So by converting the data, we can make it more useful for whatever we want to do.