Tooltips are small, interactive, textual hints for mainly graphical elements. When using icons for actions you can use a tooltip to give people clarification on its function.
Add the data-tip attribute to your element and put the text inside it, also if needed can set position using data-tip-position attribute add either top, bottom, left, right on data-tip-position to control the position.
Active Tool Tip
Also can make the Tool tip shown by default by adding .tooltip-active class.