Switching text is easy in timer.
1.HTML Markup

<!-- Slider -->
<section class="cd-intro">
    <h1 class="wow fadeInUp animated cd-headline slide" data-wow-delay=".4s" >
    <span>HI, MY NAME IS JONATHON & I AM A</span><br>
    <span class="cd-words-wrapper">
        <b class="is-visible">DESIGNER</b>
        <b>DEVELOPER</b>
        <b>FATHER</b>
    </span>
    </h1>
</section> <!-- cd-intro -->

put your texts under cd-words-wrapper class in b tag.

We have used this plugin from codyhouse. If you are interested for more follow this link – https://codyhouse.co/gem/css-animated-headlines/