Problems with keyboard library

My programme has to write in the keyboard a letter when you press the botton. But when I compile it I get error. Why do I get this error if I have this library yet?

#include <Keyboard.h>

const int boton1= 6;

int buttonState = 0;

void setup() {
  pinMode(boton1, INPUT);


void loop() {
  if (digitalRead(boton1) == HIGH) {


Don’t post screenshots of text! That is very unhelpful. When you encounter an error you’ll see a button on the right side of the orange bar “Copy error messages”. Click that button. Paste the error in a message here USING CODE TAGS (</> button on the toolbar). It is almost never appropriate to post screenshots but in some cases it is helpful to post images. You should attach and embed the image following these instructions:

You’re compiling for an Uno, which isn’t compatible with the Keyboard library:
If you actually have a different board such as Leonardo or Pro Micro that is compatible with Keyboard then you need to select that board from the Tools > Board menu, otherwise you’ll need to buy one of those boards before you can use the library.