Input Groups in Bootstrap are used to extend the default form controls by adding text or buttons on either side of textual inputs, custom file selectors or custom inputs. Basic input groups: The following classes are the base classes that are used to add the groups to either sides of the input boxes. The .input-group-prepend class is used to add groups to the front of the input. The .input-group-append class is used to add it behind the input. The .input-group-text class is used to style the text that is displayed inside the group