Add span with .input-group-text class before <input> for input-group-prepend and add span with .input-group-text class after <input> for input-group-append.

Input Groups can use with checkboxes and radio buttons also. For it add code for .vs-checkbox-con class and .vs-radio-con.

Add .input-group-{lg/sm} class to .input-group for Large/Small addon/prepend.

Add span with .input-group-btn class and add button inside before or after <input>.

Add <button> with .dropdown-toggle class and add dropdown-menu after it to get input group with dropdown.