how can i remove a error made while adding the exit button?

You might want to change the button command from self.destroy to self.root.destroy.

Button(self.root,
    text="exit",
    command=self.root.destroy,
    font=("Bahnschrift SemiBold",15),
    bg="green",
    fg="white",
    cursor="hand2").place(x=125, y=100, width=55, height=28)

As a side note, doing label = Label(root, ...).place(x=...) does not do anything (for any widget). The value of label will be stored as None and you wont be able to reference that later to change its properties. If this is the goal, then simply: Label(root, ...).place(x=...) would work. Otherwise, you’ll have to create widgets in one line, and place them in the next lline

PS: It is a recommended practice to also include the error faced in order for ease of diagnosing. Please do refer How to ask for asking further questions.