What is the function of the button on the keyboard called Insert?

Question

Keyboard

As I understand it, when you press the Insert button. The text entered earlier should be replaced by the text entered later. But that doesn't happen. I have two assumptions about this:
1. I did not fully understand the functionality of this key.
2. For some reason, the key does not work, although I also do not see any prerequisites for this.

Answer 1

spoiler

In text editors, you need to enable this feature by default, it is disabled. Live and learn.