How to do it...

This example shows how to create a login form with two entry instances for the username and password fields. Each character of password is displayed as an asterisk to avoid showing it in clear text:

import tkinter as tk 
 
class LoginApp(tk.Tk): 
    def __init__(self): 
        super().__init__() 
        self.username = tk.Entry(self) 
        self.password = tk.Entry(self, show="*") 
        self.login_btn = tk.Button(self, text="Log in", 
                                   command=self.print_login) 
        self.clear_btn = tk.Button(self, text="Clear", 
                                   command=self.clear_form)         
        self.username.pack() 
        self.password.pack() 
        self.login_btn.pack(fill=tk.BOTH) 
        self.clear_btn.pack(fill=tk.BOTH) 
 
    def print_login(self): 
        print("Username: {}".format(self.username.get())) 
        print("Password: {}".format(self.password.get())) 
 
    def clear_form(self): 
        self.username.delete(0, tk.END) 
        self.password.delete(0, tk.END) 
        self.username.focus_set() 
 
if __name__ == "__main__": 
    app = LoginApp() 
    app.mainloop()

The Log in button prints the values in the console, whereas the Clear button removes the content of both entries and returns the focus to the entry for username: