In addition, one of the characters can be underlined, for example to mark a keyboard shortcut. By default, the Tab key can be used to move to a button widget. The Checkbutton and Radiobutton widgets should be associated with variables. Each check button has its own variable, which can have one of two possible values, while a group of radio buttons all share a single variable. Each button then represents a single value for that variable.
Plain buttons are pretty straightforward to use.
You might wish to use such buttons anyway when developing an application. If you don't specify a size, the button is made just large enough to hold its contents. You can use the padx and pady option to add some extra space between the contents and the button border. You can also use the height and width options to explicitly set the size. If you display text in the button, these options define the size of the button in text units.