HTML tutorial

legend

The <legend> element represents a title of fieldset.

code result 
<fieldset>
    <legend>Choose number</legend>

    <input type="radio" id="num1" name="numbers" />
    <label for="num1">number 1</label><br/>

    <input type="radio" id="num2" name="numbers">
    <label for="num2">number 2</label><br/>

    <input type="radio" id="num3" name="numbers">
    <label for="num3">number 3</label>
</fieldset>
Choose number