Below we are summarizing the Bootstrap provided the important classes to use button groups.
This class .btn-group used for basic button group. Wrap the series of button using .btn class in .btn-group.
To use justified button groups with <button> elements, you must wrap each button in a button group. Most browsers don’t properly apply our CSS for justification to <button> elements, but since we support button dropdowns, we can workaround that.