How to close the Python turtle window after it does its code?

turtle.bye(), aka turtle.Screen().bye(), closes a turtle graphics window.

Usually, a lack of turtle.mainloop(), or one of its variants, will cause the window to close because the program will exit, closing everything. turtle.mainloop() should be the last statement executed in a turtle graphics program unless the script is run from within Python IDLE -n which disables turtle.mainloop() and variants.

turtle.Screen().mainloop() and turtle.done() are variants of turtle.mainloop().

turtle.exitonclick() aka turtle.Screen().exitonclick() binds the screen click event to do a turtle.bye() and then invokes turtle.mainloop()